If you're a player of Blizzard's World of Warcraft, you'll find this pretty interesting. There's an Open Source application on SourceForge called WoWMapView. It reads the map files from your WoW folder and lets you explore them in 3d space. It has no T&L capabilities, but it's pretty interesting to roam around. I especially enjoyed the Developer Island.

http://wowmapview.sourceforge.net/