We have an embarrassment of outdoor music events in San Francisco, and yet there's always room for more, right? That's what the organizers of this weekend's free 20th Street Block Party are hoping, and for good reason. The party's music lineup consists of of local favorites like the dance-pop duo James and Evander and rising bluesman Quinn DeVeaux, with headlining sets from indie-pop weirdo Mac DeMarco and the raunchy roots-rock assault of Two Gallants. There will be food on hand from oft-championed local kitchens like Flour + Water, Blowfish, the American Grilled Cheese Kitchen, and more; drinks will be served by bartenders from nearby establishments Bender's, Trick Dog, and Jay 'n' Bee Club. There will even be cooking lessons in the "Food Workshop Tent" (which, okay, sounds a little froofy to us). But with a solid music lineup, a nice location in the Mission, and plenty of refreshments, 20th Street Block Party should make a fine addition to the city's crowded calendar of outdoor music events.