ART: It's another titillating night of the SF Sex Worker Fest. Army of Lovers presents Formerly Known As, a two day festival of performance, art and video by male sex workers. Flavorpill tells us to "expect insight into transgender issues in the sex-work community, stories of disastrous porn shoots, and nude body art."

8 p.m. // Center for Sex and Culture (290 Division, Suite 405) // $10-20, sliding scale

MUSIC: The epic monthly music showcase Penny Arcade is celebrating it's fourth anniversary tonight. Featured bands are always reliably stand-out acts in the indie, rock, folk, psychedelic, and Americana genres, whether they be established or up-and-coming. Tonight's line-up includes The Junior Panthers, The Aerosols, Eric Shea, Pancho San, and Dusty DiMercurio. Check out SFist's interview with organizer/host Raul Sanchez.

8 p.m. // The Make-Out Room (3225 22nd St) // $6

PERFORMANCE: It's back, and in a bigger venue. Ask Dr. Hal! 2.0: Conversations with Dr. Hal! is an interactive intellectual salon in which the audience has the opportunity to consult the "omniscient and oracular" Dr. Hal Robins, aka Dr. Howland Owll, on life's "eternal questions and trivial minutiae." Pete Goldie will lead the audience "through the cosmos," KrOB will perform, and Jarico Reesce of Cyclecide Bicycle Rodeo hosts.

9 p.m. // S.P.A.C.E. (354 Fifth St) // $10, pay what you can, BYOB