With all the hype over hydrogen fuel cells (still not very feasible), Denny Klein has been silently developing a unique way to generate a gas called HHO. It has the benefits of burning hotter than hydrogen while maintaining the stability of water. At first he was just looking for a better way to weld but soon realized he'd developed an inexpensive and environmentally safe way to fuel just about everything.
He's already working with the military and major auto manufacturers.
Here's a link to his site