Roo Trimble's single gallon.

Roo Trimble has been holed up in his backyard shed for months. Hunched amid whirring saws and jagged metal scraps, he has been welding the aluminum skeleton of a small car, smoothing the joints between the latticed pipes, aligning the wheels, and climbing in and out of the metal hull to make sure he can fit snugly inside.

Trimble hopes the three-wheeled, almond-shaped contraption will carry him to victory Thursday in a first-time event called the One Gallon Challenge. As part of the second Boston GreenFest, Trimble and six others will attempt to drive their homemade cars from Greenfield to Boston City Hall Plaza, a distance of 100 miles, using just 1 gallon of gasoline.

Via: Boston.com