Can you find Missouri on a map? How about on a map without any state boundaries? Try the USA Trivia Map game above. It gives you 15 seconds to find each state by placing a pin on a satellite map of the U.S.A. If that is too easy, then try the CrunchFood map game below, which requires you to correctly identify eating spots in Palo Alto, CA near TechCrunch headquarters. Or you can try to Pin The VC, by locating venture capital offices on Sand Hill Road (I have trouble telling them apart even when I am driving around).
All of these map games were made on UMapper with its new GeoDart game creator. GeoDart lets you pick a map (choose from Microsoft, Yahoo, Google, CloudMade and OpenStreetMap), add locations, and give it a title, description, and rules. Then you can publish it and share it.
The games typically require players to find locations on the map, and then it tells gives out points based on how close they get. Here is a video describing how to make a map game with GeoDart: