ruphus13 writes "The race for a hyper-fuel-efficient car is on in a big way. Now, Riversimple has tried to leverage the knowledge of the masses to bring its vision to reality soon with a car that gives the equivalent of 300 miles to the gallon. 'The idea to build an open source car isn't a new one, but you've got to give vehicle design company Riversimple credit for originality. The company plans to unveil its first car in London later this month, a small two-seater that weighs roughly 700 pounds. If you agree to lease one for 20 years (yes, 20), Riversimple will throw in the cost of fuel for the lifetime of the lease...The team decided to release the car's designs under an open source license in order to speed up the time it takes to develop the vehicle while also driving down the cost of its components.'"