Be an urban explorer and hike up through Chinatown up Nob Hill to this FREE museum. I think seeing the inner workings of the cable car system is fascinating, but others may not be as enamored. I was thrilled to find an authentic old street sign from MY street in the gift shop, and yes I shelled out the bucks to get it. Treat yourself with a stop at one of the big hotels or small cafes a couple blocks up.