A talit should be primarily white.  Here are some details:

• A talit gadol should be either all white or white with black stripes. Avoid a very colorful talit that makes the white part look insignificant.
• Blue stripes used to be used: as with techelet, the blue reminds us of the sky, of God's throne (kisei ha'kavod), and of God.
• Even though the talit was originally supposed to have blue stripes, it is not the custom today to use blue stripes.
• Black stripes have no significance or importance.

You may not do “expert” or “professional” work of certain types on chol ha'moed, and some types of expert craftsmen/women may not do their trades on chol ha'moed.
Examples

• You may sew or lay bricks or other such labors, but not if you are an expert or professional in those fields and you are doing expert work.
• Skilled writers and artists may not do their professional writing, calligraphy, or drawing (even for free!) on chol ha'moed. They may not do calligraphy or sofer work (Torah, tefilin, mezuza), but they may write normally.
• If you are not a professional writer or expert craftsman/artist, you may write on chol ha'moed but the preferred practice is to use a shinu'i --an altered method of writing, such as:
  • Using your other hand,
  • Holding the pen/pencil differently from normal, or 
  • Writing diagonally across the paper.

The limits of kilayim keep:

• Individual creations true to themselves, in the way they were created by God, and
• Different, or opposing, spiritual forces governing creation in their own places and within their own bounds.

In the holiness of the Tabernacle or Temple, where opposites were peaceably and constructively resolved, kilayim in the form of sha'atnez was not only permitted but formed the foundation of all main tapestries and two of the High Priest's garments. Kilayim-type laws apply today to:

• Animals (not yoking an ox and donkey together; not interbreeding, say, a horse and a donkey to produce a mule),
• Food (not eating milk with meat),
• Clothing - not wearing a garment made of a mixture of linen and wool (sha'atnez), and
• Plants (interplanting, interbreeding, and grafting different species).
  Note Vineyards in Eretz Yisrael may only be near fruit trees if:
  1. A wall divides fruit tree and vineyard, OR
  2. The vineyard is not a bona fide vineyard. A bona fide vineyard has at least 5 grapevines in at least two rows, with at least two vines in one row and three in the other. 

Yom Kippur is the Day of Atonement. In ancient times, it was more festive than now and unmarried people of both genders would meet and try to find their future spouses.
Yom Kippur is a serious but also a happy day, since all Jews who repent (do teshuva) have their sins forgiven on that day.
Teshuva has four main parts:

• Charata  Regretting what we have done and feeling bad about it.
• Vidui  Recognizing and admitting that we have done something wrong.
•  Kabala  Resolving not to repeat that mistake.
• Azivat hachet  Being in the same situation as before but avoiding doing the sin.

The Torah tells us that there is an inherent property to Yom Kippur that causes spiritual purification and removes sins.
All Jews can become like angels on Yom Kippur.  In order to imitate angels (which are spiritual beings), we abstain from five activities that are associated with physical beings. We do not wash, anoint our bodies, eat or drink, have intimate relations, or wear leather shoes. To further imitate angels, when we say the shema, we say Baruch shem kevod malchuto l'olam va'ed out loud, as opposed to the rest of the year, when we say it quietly.
For more on fast days, see Fast Days.

Selecting Good from Bad and Bad from Good
Boreir Principle #1: You may eat anything in the manner in which it is normally eaten.
ExamplePeeling an orange.
 
Boreir Principle #2: You may not use a specialized tool.
 
Boreir Principle #3: You may not remove “bad” from “good.”
What To Do  Take good (edible or desired food) from the undesired (bad) components.
Note You may do this only when you are ready to eat it or when you are preparing the food to be eaten soon afterward.
 
Note Boreir is a complicated area of halacha. Because issues of boreir are almost always from the Torah (d'oraita, not d'rabanan), we are stringent in applying restrictions concerning boreir. Consult a rabbi for specific questions.
 
Selecting Undesired from Desired Food
On Shabbat, you may not usually separate totally undesired from totally desired food in a standard way, even without a specialized tool.
    NOTE As on Jewish festivals, an action needed to eat a food normally (derech achila) does not violate the prohibition of boreir on Shabbat. So you may peel a food that is normally separated from its peel or shell in order to be eaten, as long as you do not use a specialized instrument to do so. For example, on Shabbat, you may do the following by hand without a shinu'i:

• Peel an orange
• Remove the shell of a hard-boiled egg
• Separate peanuts from their shells.

NOTE If peanut shells are then put into a container that also has unshelled peanuts, you may not remove the empty shells from that mixture!
SITUATION You want remove dirt from a carrot's surface on a Shabbat.
WHAT TO DO You may remove the dirt with an altered method (shinu'i), such as scraping the peel with a knife (which is a tool not specialized for separating food)-- but not by using a peeler.
REASON The normal way to eat the carrot is to peel it.
 Selecting Desired from Undesired Food
 
While eating food (and some time before--within the amount of time you would normally need to prepare a meal), you may select desired food from undesired (or inedible) substances by hand or non-specialized tool. You may not use a specialized implement.
EXAMPLE You may remove fish from its skeleton even before eating it, but you may not remove the skeleton from the fish (because you have removed bad from good).
NOTE Once Shabbat has begun:

• You may remove fish bones from fish while you are eating the fish, but not before you are eating the fish.
• You may cut open a melon such as a cantaloupe and shake the seeds out (this is because some of the seeds remain), or take a bite of the melon and spit out the seeds. But you may not remove any remaining seeds using your hand or an implement.

EXCEPTION If you take undesired elements along with the desired food, it is not considered to be separating:  you may use a specialized tool and it does not have to be eaten soon (within the normal food-preparation time).

Almost all mitzvot may be enhanced by:

• Making them beautiful (hidur mitzva), or
• Observing non-required stringencies (mehadrin).

Who Is a Mourner

A mourner is defined in halacha as someone mourning during the 12-month mourning period for parents or the 30-day mourning period for the other five relatives (spouse, brother, sister, son, daughter). After 30 days, one is no longer a mourner for anyone but one's parents.

Mourners' Restrictions

If the mourner goes about business as usual, it may show he or she doesn't care about the close relative who died. The mourner should ideally not want to do these things. The mourner honors the dead person by refraining from pampering him/herself and refraining from going about his or her life as usual.

Public Meals

A mourner may not attend a public meal for any purpose. For example, if the mourner attends a lecture or Torah class at which food is being served, he or she may not eat the food. This only applies to sit-down meals; snacking is permitted.

Siyum/Brit/Bar Mitzva

After 30 days after a parent's burial, a mourner may:

• Attend a siyum or bar mitzva and eat there.
• Attend a brit but not eat there.

Note If there is music (live or recorded), the mourner must leave.

Weddings

A mourner may not eat at a wedding and may not even be in the wedding hall after the ceremony took. The mourner may also not hear the music at a wedding.

Exceptions

• If the mourner is the parent of someone getting married, the mourner can fully participate in the wedding.
• If the mourner is the bride or groom, he or she must normally wait to get married until after shloshim/30 days.

Note If it is after shiva, but still during shloshim, consult a rabbi.

Kiddush and Shabbat or Festival Meals

A mourner may not publicly (noticeably) mourn on Shabbat or festivals so he or she may attend Shabbat or festival meals and kiddushes if he or she would be expected to attend. If the mourner always or routinely invites some person or a lot of different people on Shabbat or festivals, it is still permitted. If the mourner does not routinely invite some person or a lot of different people to a Shabbat or festival meal, then he or she may not, for his or her own enjoyment, invite guests for meals. However, the mourner is permitted to do so for other purposes (for the benefit of the invited person or people), such as kiruv or hachnasat orchim. There is no limit to how many guests the mourner may host.

The mourner may attend or host a sheva brachot in his/her home.

A mourner should not be invited to meals, even for Shabbat or festivals; but if he/she was invited, he/she may go.

Holidays

A mourner does eat at a Purim or Jewish festival seuda, since there is no mourning on Purim nor on any festival (except Chanuka).

Tachanun is related to judgment. Tachanun is NOT said at times of din/judgment:

• At night,
• On Tish'a B'Av,
• In a house of mourning, and
• Yom Kippur.

Tachanun is also NOT said at times of simcha/happiness:

• Shabbat,
• Jewish festivals,
• Rosh Hashana, and
• Rosh Chodesh.

• Isru chag (the day after each of the Jewish festivals),
• Entire month of Nisan.

• All of Chanuka, Purim, Shushan Purim, Tu B'Shvat, Rosh Chodesh, and from Rosh Chodesh Sivan until the day after Shavuot.
• Tishrei from shacharit before Yom Kippur until after Simchat Torah (Shmini Atzeret in Eretz Yisrael). Resume saying tachanun:
  • Second day of Cheshvan, or
  • Day after isru chag of Simchat Torah (this is the more prevalent custom among Ashkenazim). Each person should follow his or her family or community custom.

• Mohel,
• Sandak, or
• Father of a boy having his circumcision.

Three Shabbat Meals
We are required to eat three Shabbat meals, as a rabbinic (d'rabanan) enactment to enjoy Shabbat (oneg Shabbat). The first Shabbat meal must be at night and the remaining two must be during the day (the third meal must be eaten after halachic midday). Friday night dinner and the first meal on Saturday are preceded by kiddush. For the first two Shabbat meals, say ha'motzi over two complete loaves of bread, each of which is at least 1.3 fl. oz. in volume. For the third meal, the ideal is to use two complete loaves of bread, but the requirement of eating the third meal can also be fulfilled by eating any food other than salt or water.

Source of Saying Shabbat Kiddush

• Saying kiddush on Shabbat night is a commandment from the Torah (d'oraita).
• Saying kiddush on Saturday morning is a rabbinical (d'rabanan) enactment.

Note If you did not say Friday night kiddush, you must say that version of kiddush on Shabbat morning and it is then a requirement from the Torah (d'oraita). Do not begin with va'yechulu; instead, begin with borei pri ha'gafen and say the second blessing of kiddush.

Source of Kiddush Location
Saying kiddush at the place where you will eat your meal is a rabbinical (d'rabanan) enactment.

Shabbat Kiddush-Meal Quantities: Evening

• For evening kiddush, a minimum of 4 fl. oz. (119 ml) of wine must be blessed on and at least half must be drunk.
• For the evening meal, as on Shabbat lunch and all required Jewish festival meals, a minimum of 1.9 fl. oz. of bread must be eaten within four minutes.

Shabbat Kiddush-Meal Quantities: First Meal on Saturday
Shabbat day first meal has two separate eating requirements.  They may be combined (say/hear kiddush and start the main meal right away) but are often done separately (say/hear kiddush and then eat some mezonot; the main meal is eaten later in the day).
Note Since eating and drinking requirements on all morning kiddushes (both Shabbat and Jewish festivals) are d'rabanan, the required beverage amount for morning kiddush is only 3.3 fl. oz. (99 ml) instead of the d'oraita 4 fl. oz. (119 ml), which is required for kiddushes for Shabbat evening.
1) Morning kiddush requires a halachically legal “meal” with these elements:
      a) Blessing on a minimum of 3.3 fl. oz. (99 ml) of wine (or other beverage),
      b) Someone's drinking at least 2 fl. oz. of the beverage, followed by
      c) Eating at least 1.3 fl. oz. (39 ml, or 1/6 cup) of some type of mezonot (or bread) within four minutes.
Note If you drink at least 3.3 fl. oz. (99 ml) of wine within 30 seconds, you do not need to eat mezonot.
Note You do not need to drink the wine or other kiddush beverage to fulfill “establishing a meal.” You may hear kiddush and then simply eat the required amount of bread or mezonot. This applies to Shabbat or Jewish festivals, evening or morning.
The kiddush “meal” does not have to satiate.
Note If you have not fulfilled the requirements for kiddush, you may not eat other foods, such as fruit or fish at a kiddush.

2) The real meal (kovei'a se'uda) of Shabbat lunch requires eating at least 1.9 fl. oz. (56 ml) of bread (or matza during Passover!) within four minutes. It should include enough food to satiate.
Note You can simultaneously fulfill the requirement to “establish a meal” and to “eat a meal” by eating one (the same) piece of bread.
For details on fulfilling the first two meals' requirements, see Shabbat: Kiddush.

Shabbat: Eating a Meal Requirement: Third Meal
For details on fulfilling the third meal's requirements, see Shabbat: Third Meal (Se'uda Shlishit).

It is praiseworthy to tell the story of Passover even if you know all the details and interpretations (as did the great rabbis of the Talmud), because of the principle of “in order to remember” (lema'an tizkor): that we should remember everything God did for us when taking us out of Egypt.
The Three Discussion Points
The most important part of the seder is discussing:

• Passover offering (Pesach),
• Unleavened bread (matza), and
• Bitter herbs (maror).

These three segments should be read from the Passover hagada in the Hebrew.  If anyone does not understand the Hebrew, these paragraphs and the concepts they express must be explained in whatever language he or she can understand.
Children at the Seder
Children are an integral part of the seder.  We try to get children to ask questions and then we teach them the answers.  The Torah says to do this!
Acknowledging God's Miracles
We acknowledge God's miracles in sending the plagues against the Egyptians and their gods and in taking the Children of Israel out of slavery and Egypt.
Telling Our History
We tell our history beginning with Jacob (Yaakov) and Laban (Lavan) and on to slavery and, finally, to achieving freedom.
 

K'zayit is variously defined as being the volume of 1/3, ½, or 1 whole egg; 0.6 - 1.9 fl. oz. (18-56 ml), depending on the application.

• K'zayit for Seder Matza and Afikoman:  1.9 fl. oz. (56 ml) of matza.
• K'zayit for Bracha Achrona and Birkat HaMazon: 1.3 fl. oz. (39 ml, or 1/6 cup) of solid food.

Beitza, K'Beitza = 1.9 fl. oz. (56 ml); an egg size by definition.

To fulfill the two requirements for Jewish festival evening kiddush:

1. Make Kiddush
   Say, or hear, the three Jewish festival evening kiddush blessings/segments:
   1. Borei pri ha'gafen (if on wine or grape juice—preferred option), OR
      Ha'motzi (on two challot if you have no wine or grape juice, since no chamar medina is allowed for Jewish festival evening kiddush; see Jewish Festivals: Kiddush: Challot for Kiddush) AND
   2. Asher bachar banu mi kol am.... mekadeish Yisrael v'hazmanim, AND
   3. She'hecheyanu on all Jewish festival nights, except the last two nights of Passover.  So say she'hecheyanu on:
      • Both nights of Rosh Hashana (in or outside of Eretz Yisrael),
      • First two nights of Passover (1 night in Eretz Yisrael),
      • Both nights of Shavuot (1 night in Eretz Yisrael),
      • First two nights of Sukkot (1 night in Eretz Yisrael), and
      • Nights of Shmini Atzeret and Simchat Torah (same day in Eretz Yisrael).
      Note There is never any requirement on an indvidual to drink kiddush wine (except at the Passover seder), but the kiddush wine must be drunk by one or more persons.
      Note A woman who had said she'hecheyanu when she lit the Jewish festival candles does NOT say she'hecheyanu again if she makes kiddush for herself, even when making kiddush at the Passover seder.
      Note There is no need to eat a new fruit after saying she'hecheyanu on the second night of  Shavuot, Passover, or Sukkot. This is not comparable to Rosh Hashana, since the second festival night was instituted due to uncertainty of the actual date of the holiday, while Rosh Hashana is considered to be one single, long day.
2. Establish a halachic “meal” (kovei'a se'uda).
   For how to establish a halachic meal, see Introduction to Jewish Festival “Eating a Meal” Requirements.

We are required to eat two meals on Jewish festivals, each preceded by kiddush, one in the evening and one in the morning. For both meals for each Jewish festival day (and all three meals on Shabbat), say ha'motzi over two complete loaves of bread, each of which is at least 1.3 fl. oz. in volume. 

Source of Saying Jewish Festival Kiddush
Some kiddushes are commanded by the Torah (d'oraita); the others are from Chazal (d'rabanan), as follows:
Kiddush d'Oraita

• First night of Jewish festivals
• Night of seventh day of Passover
• Night of Shmini Atzeret.

Kiddush d'Rabanan

• First day of Jewish festival
• Second night of Jewish festival
• Second day of Jewish festival
• Seventh day of Passover
• Eighth night of Passover
• Eighth day of Passover
• Shmini Atzeret day
• Night and day of Simchat Torah.

Source of Jewish Festival Kiddush Location
Saying Jewish festival kiddush at the place where you will eat your meal is a rabbinical (d'rabanan) enactment.
Jewish Festival Kiddush-Meal Quantities: Evening

• For evening kiddush for a first-night (d'oraita) Jewish festival, a minimum of 4 fl. oz. (119 ml) of wine must be blessed on and at least half must be drunk.
• For evening kiddush for a second-night (d'rabanan) Jewish festival, a minimum of 3.3 fl. oz. (99 ml) of wine must be blessed on and at least 2.0 fl. oz. must be drunk.
• For the evening meal, as on the first two Shabbat meals and for all required Jewish festival meals, a minimum of 1.9 fl. oz. (56 ml) of bread must be eaten within four minutes.

Eating Requirements for Jewish Festival Morning Kiddush
There are two separate eating requirements during the daytime. They may be combined (say/hear kiddush and start the main meal right away) but are often done separately (say/hear kiddush and then eat some light foods and beverages; the main meal is eaten later in the day).
Note Since eating and drinking requirements on all morning kiddushes (both Shabbat and Jewish festivals) are d'rabanan, the required beverage amount for morning kiddush is only 3.3 fl. oz. (99 ml) instead of the d'oraita 4 fl. oz. (119 ml) (which is required for kiddushes for Shabbat evening and all first-night Jewish festivals).

• Morning kiddush requires a halachically legal “meal” with these elements:
  • Blessing on a minimum of 3.3 fl. oz. (99 ml) of wine (or other beverage),
  • Someone's drinking at least half the beverage, followed by
  • Eating at least 1.3 fl. oz. (39 ml, or 1/6 cup) of some type of mezonot within four minutes. 
    Note If you drink at least 3.3 fl. oz. (99 ml) of wine within 30 seconds, you do not need to eat mezonot.
    Note You do not need to drink the wine or other kiddush beverage to fulfill “establishing a meal.” You may hear kiddush and then simply eat the required amount of bread or mezonot. This applies to Shabbat or Jewish festivals, evening or morning.
     

 

• The real meal (kovei'a se'uda) requires eating at least 1.9 fl. oz. (56 ml) of bread (or matza during Passover!) within four minutes. It must include enough food to satiate. 
  Note You can simultaneously fulfill the requirement to “establish a meal” and to “eat a meal” by eating one (the same) piece of bread.

“Be holy because I, the Lord your God, am holy.” Leviticus/Vayikra 19:2
 
Halacha ("The Way To Go" or "Way to Walk") guides proper Jewish behavior in all aspects of life, each day of our lives--not just in civil laws or court situations. Halacha teaches us how to behave with our families, relatives, and strangers as well as how to fulfill our religious requirements between ourselves and God.

To fulfill our role as a holy people, we imitate God's actions. Examples are visiting the sick, welcoming guests, giving charity, refraining from creative activity on Shabbat, and promoting peace between husband and wife (shalom bayit).

The true reason for following halacha is because God commanded us to do so.  We observe halacha to please our Creator and to become spiritually close to Him by doing His will and imitating His actions.

Like the word for the whole body of Jewish "laws," each rule of how to act is called a halacha (plural, halachot).

Where Do Halachot Come From?

Although you will find halachot on this site that were born only a few days or a few decades ago, the body of halacha has been around since before creation.  "God looked into the Torah and created the world," says the Zohar, and so we find the Patriarchs followed halacha even before that great law book, the Torah, was given on Mount Sinai four centuries later.
 
Many halachot are specified in the Written Torah (Jewish Bible). These halachot correspond to fuller and more detailed halachot given orally (Oral Torah) to Moses on Mount Sinai to explain the Written Torah that he received at the same time. Many halachot could not be understood from the Written Torah without the Oral Law (for example, what should be written on a mezuza scroll?) and many common practices such as making kiddush or what tefilin should look like are to be found nowhere in the Written Torah.
 
Since the Torah applies to all generations, the Torah specifies that there be wise and learned people to decide how to apply halacha to the situations of the day.  Halachot can be found in sourcebooks such as the Mishna, Gemara, their commentaries, Shulchan Aruch, Mishna Berura, and responsa (questions and answers originally sent by letter and now, occasionally, by email or SMS!) of later rabbis.
 
Sometimes a custom becomes a halacha, sometimes not.  For example, the original halacha for tzitzit was that a Jewish man who wears a four-cornered garment must have tzitziyot on each corner.  The custom, which has become universally accepted and now has the force of halacha, is that Jewish men wear a four-cornered garment in order to be able to fulfill the commandment of wearing tzitziyot.  An example of a custom that did not become a halacha is that some men and boys wear their tzitziyot outside of their shirts and pants.

Levels of Halachot

In halacha, there are three levels of what to follow or observe. They are differentiated on this website by the following terms: 

• “Must”:  Halachot that are generally non-negotiable except in extreme situations;
• “Should”:  Customs that have been accepted by the entire Jewish world (or major segments of it) and that may be overridden when necessary, sometimes even if not extreme circumstances; and
• “Non-Binding Custom”:  Customs that are not universally followed and that do not need to be followed except by people who have the tradition to do so.