We have to admit that we've been holding out on you. Howard, over at Surveyor Robotics passed a link on to us a few days ago, and we wanted to try it out before posting. Then, we got so hooked that we kind of held back a bit, not wanting to increase the waiting queue for this great online robot driving game.
It turns out that BP down in Australia commissioned an online robot driving game to promote their environmental activities. You can go to the site, get in the queue, then drive one of five robot vehicles around the course (it isn't as easy as it looks). The robots are modified versions of the popular Surveyor SRV-1 robotic vehicles used by universities, research labs, and robot experimenters all over the world.
Please note, since the robots derive their power from solar panels, and the actual course is in Australia, the game's operating hours are during the daylight times down under, Have fun!