Toto, Japan's foremost toilet manufacturer, has made a motorized tricycle that runs on human crap. The saddle is a functional toilet, and if you can muster up enough colonic motility to keep up a steady stream, you could travel the world.
Toto makes some damned fine toilets, incidentally -- we went to rather a lot of trouble to get one of the Toto toilet-seat/bidet devices imported to the UK and converted to local voltage, and never regretted it.
Lisa at TokyoMango explains:
As the person drives, he can poop into the bowl, and that poop will be turned into fuel for the car. It's actually part of a campaign that Toto is running in an effort to reduce its CO2 emissions by 50% in the next 6 years. The motorcycle will be making its way from Kyushu to Tokyo over the next month (departing in six days). Very exciting! I'm not sure who's driving but I'm sure that, in addition to having a drivers license, they had to check his stool to make sure its healthy and fuel-worthy.
TOILET BIKE PROJECT ｜ TOTO: [tototalk.jp]