Landmark Maps Game hosts more than two dozen geography games. Landmark Maps Game uses Google Maps technology as the basis for the games. To play a game, simply select one from the drop-down menu and click start. Each game gives you a series of places to identify on the map and each game has a running timer. The countries game and the states game are two of the games that have broad appeal for classroom use.

Here are some related resources that may be of interest to you:
Find Country – Improve Your Geography Knowledge
Five Interactive Geography Activities
Geosense – Online World Geography Game