Go here then!
They just did a huge renovation. Make sure you rent a car so you can drive out of the bay area and into Mountain view.
You can see the original computer called the Babbage machine:
You can also try to attend a GTUG meeting at the Googleplex if you are a developer.
There is a huge Chinatown in SF near union square and the GG Bridge, but all in all San Francisco is pretty lame.