What Pessah is about
Pessah (Passover) commemorates the story of the Exodus, in which the ancient Israelites were freed from slavery in Egypt. Passover begins on the 15th day of the month of Nisan in the Jewish calendar, which is in spring in the Northern Hemisphere, and is celebrated for seven or eight days. It is one of the most widely observed Jewish holidays.
During the celebration of this holiday, any consumption of leavened bread is strictly forbidden. In fact, biblical regulations require that all leavening be dispose of before the morning of 15th of Nissan. To this effect, every Jewish household should remove all Chametz before Pessach, eat only unleavened bread (Matzo) during the 8 days of Pessach, even using separate dishes that have never been in contact with Chametz.
The first two nights of Pessah (one night in Israel) are considered holidays. It is traditional for Jewish families to gather on the first night of Passover (first two nights in communities outside the land of Israel) for a special dinner called a seder (סדר—derived from the Hebrew word for "order", referring to the very specific order of the ritual). The table is set with the finest china and silverware to reflect the importance of the meal. During this meal, the story of the Exodus from Egypt is retold using a special text called the Haggadah. Four cups of wine are consumed at various stages in the narrative.
In Israel, Passover lasts for seven days with the first and last days being major Jewish holidays. No work should be performed on those days, with most of the rules relating to the observances of Shabbat being applied. A seder is held on the first day.
Outside Israel, the holiday lasts for eight days with the first two days and last two days being major holidays. A seder is conducted twice, on both the first and second days. In the intermediate days necessary work can be performed.