The Global Game Jam was a long, but great 48 hours, the theme of the games was extinction so could not relate that back to cars.
We made a game about saving frogs from ants with lots of poison. It can be found here:
http://www.globalgamejam.org/2011/ant-antagoniser-save-elan-frog
Was an awesome and fun experience, even if we only got a few hours sleep over the weekend, and Nortala is falling asleep on my shoulder as I type :)