A story is read: The Book of Esther; in Hebrew, it is Megillat Esther. The reading varies from the sedate and straight to the wild and humorous. Audience participation varies from the very sedate to the wild and humorous with sound and visual effects.
Unlike Rocky Horror, the participation is generally family friendly (little kids are usually present, and there is, after all, a required commandment to fulfill, namely to hear the story read). But similarities abound: even to the point of (otherwise religious) men coming to the event dressed as transvestites.
One prevalent custom performed in nearly every synagogue around the world is the custom of wearing costumes (like Halloween), originally masks. Participation in this custom is more uniform for children; nevertheless many adults also do this. Costumes are often associated with the Esther story, but can vary as wildly as Halloween costumes do.
Another prevalent custom performed by nearly every synagogue across the world is to "drown out Haman's name". Namely, when the name of Haman is read during the story (about 70 times), everyone present stamps his or her feet, boos, or whirls some kind of noisemaker (often a "gragger", which is a spinning, clacking noisemaker designed specifically for Purim). Since there is an obligation to hear every word read, the reader must finish reading the name before the noise starts, and must wait for the noise to end before continuing. Or must repeat the name and continue, if the noise actually drowned out the name. However, many people are not careful about this.
Yet another custom is for certain of the foreboding sentences to be read not in the traditional chanting tune used for The Book of Esther but in the tune used for the book of Lamentations.
Those are some of the most prevalent customs. However, many other acts of audience participation crop up into the reading, and these vary from place to place.
In synagogues I've been to:
- When the word "runners" is read (runners delivered the messages to every kingdom), the audience stamps its feet like runners.
- People boo and make noise when Zeresh's name is mentioned (Haman's "evil" wife: it's only equal rights that we boo both of them, right?) and when the words "and the king imposed a tax" are read.
- When the words "and a great cry went out over Shushan", I let loose a bloodcurdling scream, something I learned from my friend David Elkins when I was in his synagogue.
- This year there were a few vuvuzela's in the audience for use as noisemakers.
- The reader uses a faux feminine voice when reading Esther's lines in the text, and a gruff voice when reading Haman's lines. Certain lines are spoken with dramatic raising of the voice or dramatic pauses.
In normal years, in most places, this all takes place while people are still fasting from the Fast of Esther (the fast is during the day, and the first reading occurs on that night). However, when Purim falls on Sunday, the fast is pushed back to Thursday. And in Jerusalem, Purim is celebrated a day later, but the fast is still on the same day, so there is always (at least) a day break between the two.
What is the fast for? Some think it is because of when Esther fasted in preparation for intruding on the king to make her request. Some think it is for the fast that Jews did before going to war. And some think it is in atonement for whatever we must have done to bring the calamity (that was ultimately overturned into a festivity) upon ourselves. And because, though Haman is defeated, his descendants live on today.