This isn't just tonight -- it's for all month -- but it's so cool we're making it the pick of the day! Bank of America customers, you can flash your ATM card or credit card and you and a guest get into a bunch of local museums for free, free, free! (Wells Fargo card holders, you'll have to pay not only admission but also a $2.50 service charge. Kidding, kidding.) Offer applies to the SFMOMA, the Asian Art Museum, the California Academy of Sciences, the Yerba Buena Center for the Arts, Dede's DeYoung, and the Legion of Honor. We've been meaning to check out the Picasso show at the SFMOMA and now we've got no excuse!

Other events tonight:

--So clean and articulate! Senator and presidential aspirant Joe Biden's speaking tonight at the Crowne Plaza Hotel. 6 p.m., 480 Sutter Street (x Powell), $25.

--The SF Main Public Library is holding a community forum about Chinese regional culture and the Chinese diaspora to celebrate the opening of its photo exhibition "Documenting China." Also, they're screening the documentary "China from the Inside." 6 p.m. in the downstairs auditorium, free. Call (415) 553-3012 to reserve your seat!

--Storytelling and bands rocking it outside at El Rio in "A Night Of Voices." 9 p.m., 3158 Mission (x Precita), $5.

--And a one-man show about the foibles of dating, at the Marsh. 8 p.m., 1062 Valencia (x 22nd), $8-12 sliding.