Remember SimCity 2000? That was a great game. That was probably the last computer game I played for any significant length of time, and if my Macbook Pro were able to read 5-inch floppies, I'd totally pop it in and build myself a city called Yau Town.
Put the look of SimCity 2000 together with Google Maps, and you get OnionMap. Most of the site is in Korean, but from what I gather it aims to be something of a tourist guide with a little bit of social network mixed in. That part of OnionMap is a little fuzzy, but it was worth the five minutes for the maps.