The Musee Mecanique is like no other museum. It is full of working (cost you a nickel each) old arcade, midway and other coin-operated wonders. The collection, loving assembled by a father and maintained by the son, showcases fortune telling dolls (like in the movie "Big"), mechanical horse races, orchestras, Old Western towns, farms and more. Chuck a nickel or two in the nickelodeons and see what informed or scandalized folks back in 1900.
The musee is literally right behind Fisherman's Wharf. There is no entry fee. There are wonderful photos and other displays of the bygone Playland by the Sea amusement park and a small gift shop. And a coin machine for change, of course, in case.
It is a great place to bring kids and teens, but I always enjoy going, too, and it always surprises and delights visitors of all ages.
Here's a link to an SF Chronicle story about the place with photos and a sound clip with comments from owner Daniel Zelinsky and the cackle of "Laughing Sal" and some of the music of the machines playing in the background. To get there, click here, then select archives and then look for the "penny for his thoughts" feature. There is no direct link to photographer Mike Kepka's wonderful short interviews and photos of the city. While you are on the site, check out some of his other photo and sound vignettes of the city.
Here's a youtube clip of laughing sal. While she is probably the musee's most famous machine, she's not my favorite. I like the older action games and more musical pieces better. I like this one of one of the mechanical orchestra. You can't see much of the action, but I love how it sounds. Here's the index at youtube for the Musee Mecanique, but don't check out too many of the videos, you'll lose that element of surprise and awe when you finally do get to go there yourself!
(Next time I'm at the musee, I'll snap a few photos of my own and update this post. In the meantime, here's a youtube video I downloaded on the monkey band.)