The dancers of the American Ballet Theatre threw themselves a benefit victory party at the Roseland Ballroom tonight, and the floor show, like the ballet company's labor negotiations, was delayed until late in the night.

In the meantime, the more than 2,000 people who paid a minimum of $20 each to get in -- Roseland was crowded from the bandstands to the bathrooms -- took matters into their own hands and legs, and poured out onto the dance floor by the hundreds.

There, to the music of Bob January's New York Satin Swing Band, they boogied, Charlestoned, fox-trotted and tangoed into the night.

Lucia Chase, the 70-plus-year-old cofounder of the ABT, took her turn on the floor and showed the youngsters her version of the boogie.

To some New Yorkers, Roseland evokes the idea of a shabby hall and the film "They Shoot Horses, Don't They?"

But for tonight, Roseland touched up its makeup, decked itself out in fancy purple-and-rose bunting -- Loew's Kings Theatre in Brooklyn never looked better -- and brought a 1920s grandeur and eloquence back to the New York party scene.

People had fun.

The fashion plates of the evening were not the guests, not even the ones who bought the $500 tickets. ABT ballerinas, by the dozens, showed up in 1920s "flapper" dresses they had made themselves, bought, borrowed or fished out of garbage cans--but what elegant garbage cans these must have been.

The party, a fund-raiser for ABT dancers, had been scheduled before last week's settlement of the ABT's two-month labor dispute with its dancers. As part of the fund raising, tickets for a two-minute waltz with any ABT dancer present were sold for $5 each.

ABT's hardest hardcore fan, Guy Moore, said, "The women are unbelievable; I'm going to dance with all of them. I really am."

When the audience wasn't dancing -- or watching the dancing -- it was gossiping. Dance talk was the order of the night. One confirmed rumor that washed through the place was that ballerina Cynthia Gregory and her husband have moved out of their Broadway loft into an apartment on West End Avenue because Gregory "wanted a view."

Fernando Bujones has returned to New York from four months in Rio with his wife, who is five months pregnant. Ballerina Gregory congratulated her -- the former Marcia Kubitschek (whose father Juscelino Kubitschek used to be president of Brazil) -- and added, "I'm jealous."

ABT Artistic Director Mikhail Baryshnikov didn't appear, although he was invited.

International financier and socialite Paul LePerq said, "The party is great, fabulous, wonderful, at the top. The minute I stepped in I knew. It's number one."

Natalia Makarova, who performed a tango tonight, spent the early part of the evening in the audience raring to go and swamped by many of her fans. Raymond DeVilliers had sneaked into the afternoon dress rehearsal and tonight he cued the audience, "You're going to be so tickled. I screamed and I screamed and I carried on. She's so wonderful."

One of ballet's leading figures, who pleaded not to be identified by name, told all around him, "I hired two girls to tear off my clothes tonight but they got lost."

ABT cofounder Chase said, "I'm overjoyed that we're going to perform in Washington after all. We belong in Washington. We're Kennedy Center's official company and you bet it means something to me."