The Humble Weekly Bundle: Racing features a handful of racing games for discounted prices while also contributing to charity!
Right now you can pay what you want for Urban Trial Freestyle, Real World Racing Bundle, and WRC Powerslide. Purchases of $1 USD or more will unlock Steam keys. If you pay $6 USD or more you can also get DiRT Showdown and Joe Danger 2: The Movie. If you pay $9 USD or more you can pick up all of those games plus DiRT 3.
Humble provides games at discounted prices while also putting a portion of all payments towards charity. As always, the customer can split their payment how they want between charity, game developers, and Humble tip before checkout.
Check out the Humble Weekly Bundle: Racing here: https://www.humblebundle.com/weekly