SuperTuxKart is a free and open-source 3D kart racing game developed by Joerg Henrichs and Marianne Gagnon and is primarily based on Nintendo's Super Mario Kart. The game has many tracks and characters to choose from. SuperTuxKart is an improved version of TuxKart with a better interface, improved graphics and many more tracks.
Mac OS X 10.3.9 (for PowerPC) and 10.4 or newer (for Intel)
Intel or PowerPC powered Mac
Free download at supertuxkart.sourceforge.net