If you're in the SF bay area and enjoy this kind of stuff, there are lots of cool places to explore. Alameda NAS is especially good, but there are many others:
Well its not really abandoned, after all someone built a house on top of it and have refurbished the living quarters with additional living space.
That aside, one of the things I miss was not buying a missile silo in Idaho when I had the chance. I don't believe any are on the market any more. My biggest concern was the pumping bill (it required constant pumping to keep it from flooding).
Mmm, that entire silo could be refurbished as a datacenter with a living quater on top to host people who need to come to the center for work. It's in a quiet area and the snow could be use for cooling in the winter. Anyone has money to invest ? ;p
http://www.flickr.com/photos/telstar/sets/56935/