Short answers, pulled from the story.
The Israelites left Egypt in the year 1536 according to the biblical narrative. God commanded Moses to tell the people to take a lamb, inspect it for blemishes, and slaughter it on the 14th day of the Hebrew month of Nisan. That same night, they were to smear the animal's blood on their doorframes and lintels.
The name of the holiday Passover derives directly from the moment of divine passing over. This is a literal translation of the Hebrew word Pesach, which some scholars argue originally meant to have pity or to separate, rather than simply to skip over.
The total absence of leavened foods known as chametz is the most visible change in the Jewish home during Passover. This prohibition extends beyond just eating to forbid the possession or ownership of any product made from one of five types of grains combined with water and left to stand for more than eighteen minutes.
On the first night of Passover, Jewish families gather for a special dinner called a seder. The meal is divided into fifteen specific parts that parallel the fifteen steps in the Temple in Jerusalem, and four cups of wine are consumed while the story of the Exodus is retold using a text called the Haggadah.
Matzah is an unleavened flatbread made solely from flour and water that serves as the primary symbol of the Passover holiday. The Torah instructs Jews to eat only unleavened bread during the entire week of Passover to commemorate the haste with which the Hebrews left Egypt.
In Israel, Passover lasts for seven days with the first and last days being major holidays. Outside Israel, Orthodox and Conservative communities celebrate for eight days, while the intermediate days known as Chol HaMoed are imbued with a semi-festive status.