Check out this game:
About 2/3 of the way down the page on the right, click "Start Game". It shows you a Picasa photo and you have to guess where in the world it was taken. So far my best guesses were 1.1km and 12km! Crazy, but completely lucky.
Edit: Just got 0.1km, but it was Yankee Stadium and you could clearly see people wearing Yankee's gear.