They rent bikes for $20 bones a day. What he has to rent is basically what he has in stock and he deals in 2nd hand bikes so it will vary wildy. He may also give you a deal on a few days rental. May be the only place you could rent a fixie.
Custom Richie Ditta Track Bike, Eddie Merckx Corsa, Marioni Custom Pista, Dolan Cyclocross
Oh and if you're here on a saturday, you could head to Hellyer Veldrome (45min drive south of SF) and go track racing for cheap. Will need pedals, a helmet, $5 for track fees and $5 for track bike rental. Beginner session starts at 8.30 and runs until noon. Its great fun.