Purim (which means lots) is a Rabbinic celebration that occurs on 14 Adar (in February or March). Purim is one-day holiday that celebrates the victory of Esther and Mordechai over the evil Haman who plotted to kill the Jews as described in the Book of Esther. The primary mitzvot of Purim is to hear the reading of the Megillah (Book of Esther).
It is customary to boo, hiss, stamp feet and rattle groggers (noisemakers) whenever the name of Haman is mentioned in the service. The purpose of this custom is to blot out the name of Haman. We are also commanded to eat, drink and be merry. According to the Talmud, a person is required to drink until he cannot tell the difference between cursed be Haman and blessed be Mordecai. In addition, we are commanded to send out gifts of food or drink, and to make gifts to charity.
The sending of gifts of food and drink is referred to as shalach manos (sending out portions). Among Ashkenazic Jews, a common treat at this time of year is hamentaschen (Haman’s pockets). These triangular fruit-filled cookies are supposed to represent Haman’s three-cornered hat. It is customary to hold carnival-like celebrations on Purim and to perform plays and parodies.