Butanol is a poisonous alcohol that can be made from petroleum or biomass sources. Wikipedia's butanol page says that there is a fuel consumption penalty of ten percent versus petrol, but since butanol has a higher octane rating, increasing the compression in the engine would yield higher miles per gallon.
Environmental Energy Inc. is one group that promotes using butanol in cars today. Their home page features images (see above) from a cross-country road trip butanol promoters took last year in a 1992 Park Avenue Buick using B-100 (which is what they're calling 100 percent biobutanol. Don't confuse this with B100, 100 percent biodiesel). They also claim the car got increased gas mileage on butanol (24 mpg vs. 22 mpg on standard gasoline). EE Inc. is run by David Ramey and is based in Ohio. The company has developed a two-stage fermentation process for biobutanol that can yield 2.5 gallons of biobutanol from a bushel of corn.
[Sources: Wikipedia, Butanol.com]