The latest after-dark craze has exploded at the Union Square celeb hangout Spa, where dozens of groovy young things performed amateur strip shows in from of 800 cheering revelers last week.

Those game enough to strip were given vibrators and other sex toys as prizes. Before stripping onstage, the revelers - who included Web designers, stockbrokers, university lecturers and lawyers - signed release forms allowing event organizers to use the film and photographs on the Internet and in magazines.

Matthew Nea, a 27-year-old Web producer who attended the event said: "I thought it would be a weird thing - watching normal people take it off in from of everyone but it was lightheaded fun. It makes you wonder why this sort of thing wasn't happening before in New York.

The strip shows were organized by CAKE, - an Internet-production and entertainment company that says it aims to promote female sexual culture.

CAKE boasts that its email club has over 10,000 members mainly New Yorkers.

Admittance to the event was strict. Men were allowed in only if they were accompanied by a woman who was invited by e-mail to the event. Invitees had to RSVP. And one who attended was allowed to take part in the strips.

Jenny Schulder, 26, a Brooklyn photographer who stripped for the first time, said New York was finally wanted to "shake its booty" in a new age of sexual freedom reminiscent of the 1960s and '70s.

"It's interesting seeing how many people want to be seen doing some pretty perverse things," she said. "Everybody wants to be watched these days - just look at all the reality shows."

Another first-time performer, a 35-year-old college philosophy lecturer, handed a pair of scissors to a crowd members to cut looks her fishnet pantyhose.

"People have been repressed in New York - the clubs have been cracked down on - and now people are busting loose with what's underneath," said the lecturer, who asked to use her stage name, "Fatimire."

CAKE founder Melinda Gallagher said there had never been a "really loose, competent atmosphere in New York for heterosexual crowds which wasn't controlled by guys."

"This was an atmosphere promoting fun sexuality where females were the ones pushing the envelope, where you can fulfill you fantasies and be as wild as you want to be without any pressure," she said.