[>Download:
http://repository.rigsofrods.com/ <] Download is big green button, Top left corner.
Rigs of Rods is a free Vehicle simulator that implements Softbody physics. You can drive anything from typical cars, to boats, Fly planes, operate machinery, etc.
It's also multiplayer, though i have not figured out how to do so yet. The download link is the repository for UCC, so you can download more files for the game. There was a very recent update, which added new Vehicles and Maps.
Repost because previous thread lacked, and RoR just updated.