The 35,000-square-foot project is known as “Gym U” — as in University — and opened with a packed VIP party on May 31, and to the public on June 2. It’s located at 215 W. 23rd St.

On Thursday night, around 9 p.m., revelers in silver sequins and knee-high boots walked into Gym U NYC, David Barton ’s new gym in Chelsea, carrying toys like trucks, dinosaurs and board games ...