Sutro Project / Cable Car Museum
Those interested in the mechanics and history of the cable cars will not be disappointed!
Admission is free, and the "museum" actually powers the three surviving Cable Car lines - with live (and smelly) engine grease, churning gears, and squeaking cables, it's a great museum for children.
Address: 1201 Mason Street, SF, CA
Website: http://www.cablecarmuseum.org/
Wikipedia: http://en.wikipedia.org/wiki/San_Francisco_Cable_Car_Museum
