Vega Strike is a 3d OpenGL Action Space Sim for Win/Lin/Mac allowing players to trade, bounty hunt, or explore in a vast universe.
Active development is now on https://github.com/vegastrike and on http://www.vega-strike.org
Vega Strike is mod ready and network playable.
realistic truck & car simulator, with OpenGL graphics
update:
https://sourceforge.net/projects/newctruck3drally/
It's a 3D, physically realistic truck/car simulator, oriented to dirt tracks. This is subsancially kept as hystorical. The environment is a hilly terrain which can also be user-defined in the form of a Bitmap image file (where intensity of red component defines height). It's similar to the classic "Terep 2".