For sightseeing, most of SV is nondescript -- office parks, suburbia, strip retail. It's just the concentration of recognizable tech names, and a few signature campuses, that will catch your eye.<p>In the valley, the Computer History Museum, the Stanford Campus (and nearby Palo Alto), Fry's Electronics (especially the flagship store in Sunnyvale), and Weird Stuff (also Sunnyvale) could be worthwhile stops to get the regional vibe.<p>The recommendation to look up overlapping events and attend those is a good one: their frequency and quality is one key to the tech scene.<p>In San Francisco, a walk around the Moscone Conference Center area will get you a feel for where decades of tech conferences have happened. A couple blocks away is the SF Apple Store -- though nowadays Apple's stores elsewhere are larger and more distinctive. A few blocks in the other direction from Moscone is a very high concentration of software/media/social startups (SOMA/South Park/etc.), though the buildings are mostly nondescript. The Presidio in north SF is park-like, along the bay with great views of the Golden Gate, and features Lucasfilm/Lucasarts offices, with statues of pioneers of movies, TV, and the Force.<p>Not precisely 'silicon valley', but still part of the bay area science/tech/startup scene, the Berkeley campus area across the bay is also a nice stop for many.