*FILM/OPERA: Continuing with their screenings of exquisitely filmed productions of San Francisco operas, this week the Castro Theatre presents Puccini's Madama Butterfly. You know, the opera where [SPOILER ALERT!] the fragile heroine, geisha Cio-Cio-Sa, kills herself with a dagger at the very end? Over an obsession with some American gent? Yeah, that one.

Tonight's production of love gone awry features Zheng Cao and Steven Powell, and is conducted by San Francisco Opera Music Director Donald Runnicles.

7:30 p.m. // Castro Theatre (Castro & Market) // $6-$9

SINGLES/WEB 2.0: Lonely geeks descend upon Harlot tonight for "Love 2.0: Socializing The Dating Experience at Web 2.0 Expo." ("This isn't speed dating. This isn’t social networking. This isn’t online dating 1.0." - we're told. You will be meeting "new people in a casual, yet elegant way." What? Anyway, what we do know is that "there will be an open bar for a portion of the event." That there is reason enough to attend.) We're also told that (Flickr and Moo are "meeting for pre-party libations at Kate O'Briens" tonight as well. Check out Valleywag for more Web 2.0-ish frivolity.)

8 p.m. // Harlot (46 Minna) // free (RSVP here or here)