At 11 PM last night, a six-year-old girl, a scruffy white dog, and about fifty grown-ups, some in homemade paper crowns, gathered at Congregation Beth Elohim in Park Slope. The reason? It was an impromptu “wild rumpus” to celebrate the life and work of iconic children’s book author Maurice Sendak, who died on Tuesday.

A table containing six-packs of Red Stripe and Brooklyn Lager and boxes of animal crackers were free for the visitors who arrived for an evening of singing, noisemaking, and general mischief.

After a quick reading of Where the Wild Things Are, Cantor Joshua Breitzer passed around a box of small wooden mallets and encouraged those rumpusing to play not only the massive “Jacob’s Ladder” instrument/installation currently stationed in the back of the sanctuary but “anything you can hit.” There was much cheering, clapping, and clanking. Young dudes started banging empty water-cooler bottles together, a few drums appeared, and suddenly it was really loud. (Click here to hear a 40-second audio clip of the rumpus.)

Ron Lieber, an organizer of the event, yelled over the racket that he was delighted to learn Sendak was a son of Brooklyn. “Once I realized that, I knew we had to do something, especially when it’s dark and rainy and after bedtime,” he said.

Mr. Lieber woke his daughter Talia, the aforementioned six-year-old, at 10:30 to take her to the event. She wrinkled her nose when we asked if she liked Where the Wild Things Are. “Well, I used to like it,” she said. She prefers Chicken Soup with Rice these days.

Rabbi Andy Bachman, however, was an enthusiastic fan. “Virtually everyone I know posted something on Facebook after hearing of his death. People really feel this loss. And he would have loved this,” he said.

But where are the kids?! “A lot of parents were like, ‘11 PM? Beer?’ But even so, this is a nice bourgeois Park Slope event, and we’ll do something for the kids this weekend, and say Kaddish for [Sendak],” he said.

Also in attendance was Debbie Caponera, the niece of Lynn Caponera, Sendak’s longtime assistant and caretaker who was with him when he died. What would Maurice think of the strange scene in the sanctuary tonight? “He’s definitely watching and enjoying it, and he’s glad people are happy,” Ms. Caponera said.

The evening devolved into a raucous freakout. The young, energetic cantor (who at one point urged attendees to check in on Foursquare) sat down at the piano and hammered out the chords of Nirvana’s “Smells Like Teen Spirit” accompanied by a saxophonist, while Rabbi Bachman hollered a sort of beat-poetry version of Sendak’s writing into a microphone.

And then, at midnight, a chocolate cake with “I Will Eat You Up!”—the trademark threat issued by Max in Where the Wild Things Are—written in icing was cut and shared.

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