Photos: At Eco-marathon, a race to burn less fuel

To get really, really, really good gas mileage, you need a small, lightweight, and aerodynamic car, and all the parts need to fit just right. In the Eco-marathon, the team that gets things really, really, really right will win a $10,000 grand prize. There are also smaller awards in the internal combustion, fuel cell, and solar categories.

Solar-powered vehicles are not eligible for the grand prize, according to the rulebook, because they "do not use 'fuel' and the solar energy that is used is limitless and cannot be converted into an equivalent measure to compare to other engine types."