Purdue University researchers have developed a "tactical biorefinery" that generates electricity from food, paper, and plastic trash. Food waste is fermented into ethanol; other trash is heated under low-oxygen conditions and is converted to propane and methane gas. The mix of fuels is burned in a modified diesel engine.
Apparently they got funding for this because it has military applications (reducing the need for fuel to troops in the field, as well as disposing of much of their trash). But the civilian applications are obvious. It's too bad that under our crazy system, technology pretty much has to have military applications to get public money for research.