Geoguessr plops you down in a random place on Google's street view. Use the street view controls to try to figure out where you are, and enter your guess on the map. Each game gives you five locations.
My top score so far is 17,000 and change.
You have to hunt for clues to your whereabouts - street signs? What language are they in? What side of the road are people driving on? What's the vegetation look like? What about the general state of road engineering?
I can't stop playing.