Martin Fussen tipped us off to PlaceSpotting, a user-contributed geo quiz map mashup. The idea is to create puzzles for your friends to solve by picking an obscure landmark and supplying them with a few hints. Your friends can then zoom around on the map to find the location. If they position the map at the right zoom level and over the location the puzzle is solved. I have to say this is a pretty fun way to learn a bit about the world, especially if you’re in to puzzles and treasure hunts.
You can search and browse a large library of entries that other people have created. There are a significant number of entries in German, and many of the landmarks are within Europe, but there’s nothing stopping you from dropping a few landmarks near the place you call home.