VDrift is a cross-platform, open source, drift racing simulation game released under the GPL and available for Linux, FreeBSD, Mac OS X and Windows.
VDrift features over 20 real world tracks and almost 30 cars to choose from. The game has a very realistic physics and the tracks, scenery and terrain modeled in acceptable details. The game is intended to run on slower machines with GeForce 2 and later, so you can’t compare the graphics with today’s games. But the effort put by the developers on a non-profit project like VDrift is admirable.
The game includes such basic features like different camera modes, replays, customizable controls, automatic shifting, traction control, anti-lock braking etc. It supports joysticks and gamepad and also has an experimental force feedback feature.
I haven’t played it yet but from the screenshots the game looks promising.