The joyful Feast of Purim celebrates a "close call" that the Jewish people had.
If you don't know the story, read the Book of Esther in the Bible.
Reading the Book of Esther is one way that we celebrate Purim.
Traditionally we attend a reading in the synagogue. (From a long scroll, sort of like this long Dry Bones Purim Web page)
The fight of Queen Esther and her Uncle Mordechai against the wicked Haman is read aloud, during which the entire congregation, led by the children, make loud noises, often with rattles, to drown out Haman's name.
Obviously the saving of one Jewish community in ancient Persia is not what makes the joyous Purim holiday so significant.
And the characters of "Queen Esther" and "Mordechai the Jew" are NOT what makes the holiday tick.