Purim פורים
The festival of Persian Jewry's rescue: reading the Megillah, gifts, a feast and rejoicing on 14 Adar.
Purim is named for the pur, the lot Haman cast to choose a month for destroying the Jews; it fell on Adar. The decree was undone not by cancellation but by a second decree permitting Jews to defend themselves, which they did on 13 Adar 3405, celebrating on the fourteenth.
The sages call the miracle «hidden»: the Megillah contains no open miracle and no name of God, only a chain of coincidences that adds up to rescue. Hence the day's blurred edges — drinking until one no longer distinguishes «cursed be Haman» from «blessed be Mordechai».
Four obligations: hearing the Megillah twice; mishloach manot, sending two prepared foods to another; matanot la'evyonim, gifts to at least two poor people; and a festive meal. Midrash adds that in those days the nation accepted the Torah afresh — willingly this time.