There's something about defecation that seems to both fascinate and revulse humans at the same time. In other words, there's just something funny about poop and I can't explain it. I will however, direct your attention to a poop-powered VW Bug built by some enterprising Brits.
GENeco has streamlined a process that allows this VW Bug to run on methane. This has been done before, but many methane vehicles had decreased performance because the fecal fuel wasn't “clean” enough. GENeco seems to have solved this problem, and the Bio Bug as it is being called, is being hailed as a breakthough in poop-power.