IF IT'S SUNDAY, this must be Atlas. But if it's Wednesday, you can call it Car Wash. Or Cafe Society, if it happens to be Thursday. And on Friday, you're at Soiree Privee.

All these far-flung places are really alter egos of the same chameleon-like club, known the rest of the week as Fifth Column. At 915 F St. NW, this former bank-turned-nightclub enjoys a multiple-personality disorder inspired in part by the fractionalized New York club scene, where spicy variety is essential to satisfy the many factions and flavors of nightclubbers.

This past Sunday at Fifth Column saw the unveiling of Atlas, the latest of Fifth Column's designated-night sub-clubs. By 11, the line of the curious and the cool snaked halfway down F Street, and inside it was wall-to-wall, a smash-hit first night partly because of the irresistible "I-was-there" mystique of a brand-new thing; the promise of half-price drinks and bottled beer all night (still expensive at $2.50 a pop); and the combined reputation of "hosts" Darrell Allison, George Domurot and Mark Lee, co-founders of the late Adams-Morgan hotspot Dakota.

Inside Atlas's target crowd of cutting-edge gay men and women, clubgoers wedged and wiggled happily together as New York DJ Robert Renk played hot stuff like "Groove Is in the Heart" by Deee-Lite (appearing at Fifth Column Oct. 23) and basement-level DJ Ed Bailey picked hot and hyper house tracks like this summer's floorpacker "Ride on Time" by Black Box. Some of the crowd dressed up like proper first-nighters, but most showed out in dancing-efficient clothes -- those shirts were just going to come off anyway.

"We got a lot of good reaction," says Lee, who estimates that around 1,500 made it into the club, with between 500 and 750 people left in line. "I think people were really excited about something fresh and different. It was a fairly diverse crowd, we were very pleased with that. And also I think people enjoyed all the different places in the club -- the upstairs bar, the patio, the basement with its own DJ, which became its own popular hot little spot with those guys dancing in their briefs. It gives you the opportunity to move around, kind of bump into people or go see what's going on in another part of the building, yet it's large enough that there's that focused energy on the dance floor."

Lee and his partners were part of the original Dakota team, which spun off its own sub-club called Ozone on Wednesday nights (it was launched with Super DJ Dmitry, who has since gone on to chart success as one-third of the hot dance trio Deee-Lite; Dmitry was followed by New York's Larry Tee, who will spin at Atlas this Sunday and next). When Dakota changed management and ownership, the three took their time looking for another project. They had hopes for converting an abandoned deco movie house in Northeast into a club, but found it was leased for use as a dance studio. But they liked the theater's bold, strong, catchy name and kept it. The word Atlas carries lots of connotations and denotations: There's Charles, of course, and a map of the world, space exploration, radial tires . . . .

"Basically Fifth Column turns the club over to us," says Lee, a graphic designer who fashioned the club's sharp limited edition T-shirts, already a collector's item -- bartenders were turning down $20 and $50 offers for the shirts off their backs. "We brought in our own bar staff and door staff, used their porters and barbacks. It's almost like a private function or rental. We come in, give it its identity. It's kind of a club within a club."

After a summer spent sweating over the details, Lee and his partners were privately calling Atlas "At last" on Sunday night. And on Monday morning, Lee breathed a sigh of relief as he harvested congratulations (and requests for T-shirts) from his answering machine. "There's always the risk factor with something like this," Lee says. "You never know how you're going to do, but when that line began to form . . . Later, your main worry -- regret, really -- is that you can't let everyone in."

The other three Fifth Column nights are basically inhouse promotions -- working with an outside group on an ongoing basis is new for the club, says general manager Dirk Van Stockum. "We're downtown, and it's important to aggressively push and find a reason for people to come down here. We have to offer a lot of variety. You can't pack a club four nights a week by offering the same format."

The garish Day-Glo invitation to Wednesday's Car Wash night promises "disco hell," and write-in mayoral candidate Russell Hirshon among the hosts. Van Stockum says Car Wash boasts "late '70s disco, reinstigating all the worst stuff of that decade. It's really disgustingly tacky." A fluorescent Volkswagen love bug has been installed on the ceiling over the dance floor -- it spouts soap bubbles at peak moments (you get two bucks off the $5 admission price if you show up in '70s dress).

Thursday's Cafe Society, says Van Stockum, attracts "a dressy, Eurotrashy crowd, and the DJs play the kind of stuff people hear while vacationing in the south of France or the island of Ibiza." Friday's Soiree Privee is an invitation-only crowd of D.C. scenesters and Fifth Column regulars -- you can try your luck at the door, but admission is at the discretion of the doorman. And Atlas is directed toward the gay club crowd, which traditionally parties late on Sundays, while the rest of the world is tucked in early on a "school night." Call 202/393-3632.

NEAR DUPONT CIRCLE, a new club is also offering a kaleidoscopic collection of music/lifestyle choices. Owner Cengiz Kilinc wasn't exactly striking it rich with his below-street level Aspendos Cafe at 1522 Connecticut Ave. NW, so he decided to give the space a go as an alternative club in a neighborhood where straight, gay, multiethnic, tourist and residential Washington intersect. So, on Friday and Saturday nights at Club Retaliation, house DJ Olivier offers "roots-rock-reggae-ragamuffin-rap"; on Wednesdays, it's hip-hop, funk and go-go; Thursday is "XXX Hardcore Metal Night"; and on Sundays, Cengiz plans to present local rock bands. "It's not a big club -- it's small enough to get everybody to know each other but big enough to hide in the corners," says Kilinc.

"Washington is a very diplomatic city, very cosmopolitan," says Turkish entrepreneur Kilinc, explaining the club's name. "Government and politics is not what we believe. We do retaliate, not with guns or anything, just with flowers, music and love." Call 202/462-3405.