A free ball pit for adults opens in SoHo today, but don't expect to be able to stroll in off the street while your parents pick you up a couple of Happy Meals. There are only a handful of slots left at JumpIn, creative agency Pearlfisher's much-anticipated 81,000-ball play pen, because grown-ups like to swim in seas of circular plastic even more than children do. You know JD is an adult now, and he regrets squandering his one shot at fun.

The free Jumpin pit is located at Pearlfisher's new office at 455 Broadway, and individuals lucky enough to reserve a free 30-minute session can wriggle around in it while officeworkers look on longingly. At least until the pit closes on September 21st.

Spots have gone FAST—as of now, there are only a handful of open time slots, and the Pearlfisher team expects the pit will sell out entirely by the time you are finished reading this post, so snap something up NOW if you yearn to reconnect with your youth enough to risk foot-and-mouth disease.

We got a preview of the pit last night, and it's pretty entertaining, if not quite as expansive as the National Building Museum's 10,000 square-foot pit that's taken Washington, D.C. by storm this summer. Belly flops are encouraged, though one should not dive headfirst, as the ball pit is very shallow—there's also a camera onsite that will snap your photo and make a GIF of you as you pelt your friends and strangers.

Peruse the gallery above, and note that if you have managed to land a spot at the pit, a $5 donation is very much encouraged. It's hard to keep balls clean, after all.