This Thursday evening is the Divisadero Art Walk - a wonderful little streetside art show in Western Addition. Lots of neighborhood businesses have specials on food, drinks, and whatever else they vend that night too, so the night is sure to be full of fun all around. Here's the full list of who's participating and what kind of deals they're providing.
Incidentally, there's also an art walk in the galleries down by Union Square the same night, but I don't know that there's the same kind of neighborhood business participation among non-galleries. Either way, if you're looking for something to do that night, these are both great low-key pocket-friendly ways to spend your time!