If you're mechanically and environmentally inclined, a $10 million prize could soon be yours. The X Prize Foundation is offering $10 million for a super-efficient car. The competition is open to established automakers and unknown engineers, and it's meant to result in cars available for purchase, not just concept cars.

So far, more than 60 teams have signed up for the competition. The winners will participate in a cross-country race in 2009, in which they'll be judged on fuel efficiency, speed, distance and other factors. For more information, check out the website for the Progressive Insurance Automotive X Prize.