Passover Week
The eight-day festival of Passover is celebrated in the early spring, from the 15th through the 22nd of the Hebrew month of Nissan. It commemorates the emancipation of the Israelites from slavery in ancient Egypt. And, by following the rituals of Passover, we have the ability to relive and experience the true freedom that our ancestors gained.
Passover is divided into two parts:
The first two days and last two days (the latter commemorating the splitting of the Red Sea) are full-fledged holidays. Holiday candles are lit at night, and kiddush and sumptuous holiday meals are enjoyed on both nights and days. We don’t go to work, drive, write or switch on or off electric devices. We are permitted to cook and to carry outdoors (click here for the details).
The middle four days are called chol hamoed, semi-festive “intermediate days,” when most forms of work are permitted.
NO CHAMETZ
To commemorate the unleavened bread that the Israelites ate when they left Egypt, we don’t eat—or even retain in our possession—any chametz from midday of the day before Passover until the conclusion of the holiday. Chametz means leavened grain—any food or drink that contains even a trace of wheat, barley, rye, oats, spelt or their derivatives, and which wasn’t guarded from leavening or fermentation. This includes bread, cake, cookies, cereal, pasta and most alcoholic beverages. Moreover, almost any processed food or drink can be assumed to be chametz unless certified otherwise.
http://www.chabad.org/holidays/passover/pesach_cdo/aid/871715/jewish/What-Is-Passover.htm