Musée Mécanique
Once a staple at Playland at the Beach, San Francisco's early-20th-century amusement park, the antique mechanical contrivances at this time-warp arcade—including peep shows and nickelodeons—make it one of the most worthwhile attractions at the Wharf. Some favorites are the giant and rather creepy "Laffing Sal"; an arm-wrestling machine; (supposedly) the world's only steam-powered motorcycle; various retro pinball machines; and mechanical fortune-telling figures. This is a truly fun and somewhat surreal experience. Admission is free, but you'll need quarters to bring the machines to life.