SCIENCE: Drink cocktails served by actual robots and expect a "snarky" electronic bartender at the fourth annual BarBot 2011, a celebration of cocktail culture and man-machine interface. Drink up!

9 p.m. // pariSoma (169 11th Street) // $15

BOOKS: The controversial Novella Carpenter will be the guest author at tonight's April Fool's edition of Booksmith Bookswap, which is themed in the spirit of laughter and trickery. Bring a book that made you laugh out loud, had a major twist or surprise, or turned out to be different than you thought it would be.

6:30 to 9:30 p.m. // The Booksmith (1644 Haight Street) // $25

ART: Arc Studios & Gallery, which boasts ten newly renovated artist studios, a 1,000 sq. ft. art gallery, two small galleries, and an art education center, presents its Spring SOMA Open Studios. Work will be on display by eighteen artists working and exhibiting in the South of Market neighborhood, which is steadily filling up with Mission District transplants.

6 to 10 p.m. // Arc Studios & Gallery (1246 Folsom Street) // free