My friend Brian came across this today. All they did was put a car on GoogleMaps. Arrow keys move your little car around the map. There's collision detection for the roads, but it's still pretty buggy. You'll find you can drive off the streets at some points. Obviously, they let you select your desired location of where to drive, so it's kind of cool drive around your area, or even on other continents.

In their blog, they say they're looking to release a googleRacer mini game. In the game you'll be able to select a certain destination and race against the clock to get there. Nothing overwhelmingly exciting, but it's unique.