The ladies call themselves "BBW" or "big, beautiful women". The gentlemen are known as "BHMs'" or "big, handsome men". Their common interest, when they're not pounding the specially reinforced dancefloor, is the noble cause of "size acceptance".
With a black President in the White House, and laws protecting gays, women and religious minorities, America's nightclub scene is fostering a new movement to secure civil rights for one of the few social groups who can still legally be persecuted: fat people. An explosion of "plus-size" entertainment venues, where revellers of all shapes and waistlines are welcomed, is managing to tap both the economic and political potential of the country's one in three adults who are clinically obese.
In Long Beach, California, Lisa Marie Garbo, who styles herself as the voice of America's BBW "community", has begun inviting patrons at her Club Bounce to sign petitions calling for President Obama to include the overweight in proposed new employment and hate-crime laws.
She is busily spreading the word among the 400 like-minded punters who attend her venue every Friday and Saturday. "In most nightclubs, overweight people get laughed at, treated like dirt and made to wait in line for hours by doormen. We're a feel-good club: a place where anyone can come and learn to feel good about themselves."
Ms Garbo, 41, whose weight has varied, over the years, from 19 stone to 23 stone, is a descendant of the film star Greta, whose sylph-like quality was never in doubt. She was inspired to open Club Bounce after being refused entry to a Hollywood nightspot, and now plans to roll out a chain of franchised venues across the country.
"People think being overweight is a choice, and have historically used that as an excuse to deny us rights. But it's not always down to that. I'm asthmatic. I was put on steroids when I was young. I'm not a perfect eater, and I don't exercise every day, but there are other factors making me the size I am, and it should never be used as an excuse for discrimination."
Roughly 70 per cent of her male guests, and 30 per cent of female ones, are "normal sized", she estimates. Many of the "smaller punters" pay the $15 (£10) entrance fee in order to have a chance of meeting an attractive, larger member of the opposite sex. "A lot of normal-sized people are attracted to overweight people. They celebrate them," she said
Most of the nation's handful of "plus-size" venues were started in the last couple of years, to cater for a community that grew up around internet chat-rooms. To many patrons, they provide a form of therapy, helping to revolutionise social lives that were previously non-existent.
"I see myself as a stepping stone," says Kathleen Divine, who owns the Butterfly Lounge in Orange County. "A lot of people who come along might never normally go out because of their size. The more they enjoy themselves here, the more confidence they get. It can really help their self-esteem. I've had people tell me that this club persuaded them to go out and get a better job."
Ms Divine has recently widened her business empire to include a dating site for BBWs, together with a fashion label called Big Girl Gear, which sells nightclub clothing for larger women. "There's huge demand for what we do. People have flown in from San Francisco, Las Vegas, and even the UK and Australia. You would be amazed by what happens on the dancefloor. I've seen 6001b (43 stone) women dance all night. I'm 2251b, and I can't keep going with them."
Lynn McAfe, of the Council on Size and Weight Discrimination, told the Associated Press last month: "It's nice to have a place to go where you can do a little flirting and maybe bring your thin sister or somebody from work who isn't fat, and they'll be in your world for awhile. That's an amazing experience for a lot of people who aren't fat, to spend a day or night in a world of fat people."
For a few, the plus-size scene can be truly life-changing. Two weeks ago, Mike Cooper, a Club Bounce regular from Los Angeles who was recently made the nightclub's "man of the year" for 2009, was married in Las Vegas. He'd met his wife, Blondie, at the venue. "It was the third-last song of the night and I saw this woman walking across the dancefloor. I asked her to dance. We've been inseparable ever since, and it's all because of this little place," he said.
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