The Washington Post today carried this story about the "Geek Ghetto" that has grown up in Tokyo:

On streets once packed with housewives or couples shopping for refrigerators and microwave ovens, hundreds of thousands of nerds -- mostly men between about 18 and 45 -- now wander through the area's multi-story comic warehouses and elaborate game arcades. Eyeglass adjustment kiosks compete for space with shops selling nondescript dress shirts and thick leather shoes.

The article seems to provide a reasonably balanced view of this cultural phenomenon, discussing things like the sense of community and the prevelance of pedophilic imagery in that community. A good read if you're interested in the details of a startlingly different culture.