Wood gas, the original biofuel. Developed during WWII to deal with fuel shortages, wood gas can burn about any farm waste, even plastics, and turn it into fuel for cars.

From the page: "During the Second World War, almost every motorised vehicle in continental Europe was converted to use firewood.

"Wood gas cars (also known as producer gas cars) are a not-so-elegant but surprisingly efficient and ecological alternative to their petrol (gasoline) cousins, whilst their range is comparable to that of electric cars. "

Woodgas was used in Europe during WWII to power farm equipment through fuel shortages. This sustainable biofuel is making a comeback. Many websites provide a wealth of DIY information.
Up until now, every piece had to be individually designed and tweaked to get a functional system. Enter the GEK, a simple experimenter's kit that can be used to both create biofuel for vehicles, heat or electricity as well as producing biochar soil amendment to produce ever greater amounts of biomass, sequestering carbon in the process.

The GEK even has a community wiki/forum!