You mentioned in the comments you wanted to tour businesses... ...and I can second that businesses like the Googleplex and Apple HQ sound interesting but they'

You mentioned in the comments you wanted to tour businesses... ...and I can second that businesses like the Googleplex and Apple HQ sound interesting but they're pretty boring cube farms. If you know someone who works at one of the companies ask if u can have lunch with them at Apple or Google's cafes - pretty cool. But don't expect to get a tour of the offices (cube farms) - most companies are highly secretive of their workplaces and employees are not allowed to give grand tours. Googleplex is more interesting when they have events but they tend to do that less now. For startups, for me more interesting things are happening in The City (San Francisco). Take a trip up here and hang out in SoMa - many startup people hang out in cafes like Centro, Epicenter, Ritual Roasters, Maxfields, etc. Check upcoming and facebook for events that might be going on, but Monday is a quiet day usually.