The rovers Spirit and Opportunity celebrated three years on Mars this month - regular little Energizer Bunnies who just keep roving and roving and roving. Amazing engineering and amazing science, and they're cute little robot guys too. If you haven't read Roving Mars by Steve Squyres, I highly recommend it.
While looking for something related to the Moon, I happened to find this free on-line Drive on Mars simulation that like the rovers themselves, is still active three years later. It lets you drive the rovers around fairly realistic simulations of the two landing sites. It is based on an ActiveX plug-in and runs in a web browser window. On a quick test drive of Spirit, it seemed that sundown arrived awfully fast, until I noticed that time is accelerated about 60x (about one second per minute of real time), presumably because the rovers move so slowly (about 50 mm/second top speed, about 0.2 km/hour) that driving them in real time would be painfully slow. The solar powered rovers are inactive at night, but sunrise also comes around quite fast at 60x, so no worries.
You can drive manually with arrow buttons, or double click a spot of terrain to plant a red target flag and let the rover navigate itself there. There are also buttons for several different views, including the cool undercarriage view that shows how the six wheels make turns and roll over bumps. It's not exactly Grand Theft Auto (which my daughter reminds me is not really much about driving), but it's kinda fun.