FILM: The 54th San Francisco International Film Festival opens tonight with a screening of the new film Beginners, starring Christopher Plummer as a senior who comes out of the closet in the wake of a cancer diagnosis and Ewan McGregor as his unlucky-in-love son. The film is an autobiographical tale written/directed by Thumbsucker's Mike Mills. An opening night extravaganza will follow the screening, featuring culinary delights from local restaurants, sophisticated cocktails and, of course, dancing. You must be 21+ to attend the party.

7 p.m. // Castro Theatre (429 Castro Street) // $75-150

ART: The Wattis Institute for Contemporary Arts presents God Only Knows Who the Audience Is: Performance, Video, and Television Through the Lens of La Mamelle / ART COM, an exhibition produced by the graduating class of the Graduate Program in Curatorial Practice at California College of the Arts, uses the publications and archives of the now-defunct gallery La Mamelle / ART COM as a frame of reference to explore various relationships between audience and artist through photography, film, remakes, performances, ephemera, and broadcast-based works.

6 p.m. // CCA Wattis Institute (1111 Eighth Street, California College of the Arts, SF) // free

SCIENCE: Have you heard the myth about the "vanishing lake" that was supposedly located in what is now the Mission? At The Mystery of Laguna Dolores, Christopher Richard, Curator of Aquatic Biology at Oakland Museum, brings modern understanding of the city's hydrology with his re-translation of the historical documents of the founding father of Mission Dolores.

7:30 p.m. // Randall Museum Theater (199 Museum Way) // free