I wrote this quora answer, and I’m now capturing it here in preparation for Quora’s eventual demise.

• Go to the Pacific Pinball Museum in Alameda: http://pacificpinball.org/
• Check out the Stanford Dish: http://dish.stanford.edu
• Sign up for a tour of the Stanford Linear Accelerator: http://www.slac.stanford.edu/
• Check out the seabirds and learn about the ecology of the bay at the Palo Alto Baylands
• Ride with the San Jose Bike Party: http://www.sjbikeparty.org/
• San Bruno Mountain Park: Great views and explore an abandoned Nike missile base: link
• The Pirate Store (has to be seen to be believed!): http://www.826valencia.org/store/
• Borderlands bookstore (SF / Fantasy bookstore): http://www.borderlands-books.com/
• Hack something at Noisebridge: https://www.noisebridge.net/wiki/Noisebridge
• Cable car museum: http://www.cablecarmuseum.org
• Streetcar museum: http://www.streetcar.org/museum/
• Cartoon Art museum: http://cartoonart.org/
• Oakland Art Murmur (first fridays): http://oaklandartmurmur.org/
• Japantown Mall (actually quite good). Go to the stationery store and immerse yourself in pen heaven: http://www.sfjapantown.org/