The complete edition of Dirt 3 is available for a very limited period on the Humble Bundle store as part of their sales celebration. However, the game is playable on Windows and Mac only.
The third installment in the series has been developed by Codemasters and was released in May 2011 for Windows, PS3 and Xbox 360. This edition includes all the DLC which adds many tracks and cars to the base game. In addition to the main mode and gymkhana mode, there are also various party modes like smashing wooden targets, spreading zombie infection and capture the flag.
Grab the game here. It will only be available until 23:30pm of 12 November.