RdV   (Photo: Courtesy of RdV)

RdV   (Photo: Courtesy of RdV)

Upstairs: Bagatelle
Downstairs: RdV
409 W. 13th St., nr. Ninth Ave.; 212-675-2400
Short for rendezvous, this lounge—under Bagatelle, a French bistro run by Ducasse and Daniel vet Nicolas Cantrel—is indeed a good place to meet ... especially if you're a Brazilian model or an off-duty mixologist with complicated facial hair. Bonus: antique foosball!

Upstairs: Kingswood
Downstairs: Baddies
121 W. 10th St., nr. Greenwich Ave.; 212-645-0018
After going the unnamed-private-party-space route for a while, Kingswood's basement has been officially dubbed Baddies. Females abound, as do a variety of European nationals and bartenders seemingly lifted from Sydney surf shops.

Upstairs: Broadway East
Downstairs: BEast
171 E. Broadway, nr. Rutgers St.; 212-228-3100
Upstairs at 171 East Broadway may be a bit rocky, but downstairs is smooth sailing. BEast's many pluses include a killer sound system from Jim Toth, organic wines from LEED-certified wineries, and conceptual-art-type "video nights." Best of all? Bill Murray sightings!

Upstairs: Merkato 55
Downstairs: Bijoux
55 Gansevoort St., nr. Greenwich St.; 212-255-8555
An interestingly partitioned space with a bunch of tiny rooms, one even boasting a lowered chandelier gazing at its reflection in a glassed-over well. Somehow, despite the well (and the mime sightings), it's the upstairs Saturday brunch that's gotten all the attention.

Upstairs: Macao Trading Co.
Downstairs: The Basement at Macao Trading Co.
311 Church St., nr. Walker St.; 212-431-8750
Technically still nameless, this lounge is all about the visual impact: Taking cues from thirties Macao, there are opium pipes, naked pinup-girl posters, and, of course, Tibetan penis-fertility symbols.

Southside   (Photo: Courtesy of Southside)

Upstairs: Bar Martignetti
Downstairs: Southside
1 Cleveland Pl., at Broome St.; 212-680-5600
Anthony Martignetti was actually ahead of the curve on this one—his Nolita restaurant (currently closed for renovations) had a basement bar, Bella's, before the recent rash. It's been reborn as Southside, a simple, handsome spot outfitted in black leather banquettes, a black-and-white tile floor, and various flora.