Surprise! To rehearse for this weekend’s Outside Lands fest, Beck just announced a last-minute show tonight at Bimbo’s in San Francisco. It’s anyone’s guess if he’ll play songs from his next “album” Song Reader, out in December. Completely blurring that performance-art line, the folk-funk-rocker’s latest is a book of sheet music for 20 new songs with original art by Marcel Dzama and Leanne Shapton — one of our favorites. Recordings by fans and other musicians (and maybe Beck himself?) will be featured on McSweeney’s.