Via Kottke, a totally addictive game that makes ingenious use of Google Street View to test your world geography knowledge.
Geoguessr places you at a random Google Street View location and asks you to take your best guess of where you are by placing a pin on a world map. After five turns, you're given a score. The trick is to look for details in the natural or built environment to narrow down the possibilities (fans of Andrew Sullivan's weekly View From Your Window contest will find the format idea familiar).
I've noticed after playing it a few times that Australian locations come up a lot, which suggests that Google has uploaded a lot more street level images from this part of the world than others.
Image courtesy of Google.