http://www.project-torque.com
It's a sim MMORG(Racing Game) with extremely realistic graphics and physics. Totally free also. There's a very broad range of vehicles also, it ranges from offroad buggies to SUVs to RWD V8 Mustang knock-offs. It's a lot of fun and there's always a lot of people online to race. There's also several different race styles. If anybody starts playing let me know your account name.