A Gamasutra's article about a game that uses google to educate people on geography.
We wanted a game concept that was simple and fun. Since the primary goal of our project was to explore the possibilities of gaming on Google Earth, we didn’t want a complicated concept that might distract from the technical exploration at hand. Ultimately we chose a classic concept that fit Google Earth—aliens invading our planet
More info here: http://www.gamasutra.com/features/200612 28/intel_01.shtml