Sure, brain freeze can be had by quickly indulging in ice cream or a smoothie — or even a 7-Eleven Slurpee — but why go for lowbrow sweets when you can achieve cranium frostbite with the ultimate in frozen desserts? We're talking about the crazy concoctions coming out of the Inventing Room, chef Ian Kleinman's new brick-and-mortar version of the catering company he runs. Start with a simple s'mores ice cream sandwich, and as the cold starts to seep in, move on to one of Kleinman's wilder creations, like the frozen cherry-vanilla mousse with chocolate cotton candy. This dessert shop also whips out one of the city's most intense sundaes, a treat guests can design and get topped with homemade caramel pop rocks and exploding whipped cream. While all of these delights prove worth the trip themselves, part of the fun is visiting the Ballpark neighborhood shop and watching the magic the staff works with liquid nitrogen, sugar and cream.