This [Link] is pretty cool. A producer-gas fueled truck in the Australian outback. For those who haven't heard of it, producer gas is gas that is produced by heating (in a closed container) wood, charcoal or other biomass fuel. The fuel must be cooled and filtered before use. This technology has been used since before gasoline was readily available, and some farmers used producer gas in their trucks and tractors during WWII. This is similar, but not the same, as methane gas, which is produced by bacterial action and can be used for the same purposes.
It seems to me that this technology would be best used to run a generator or other stationary engine; but these folks proved that it can be used for transportation as well.