So I said cow-powered...and maybe you imagined cows pulling the ride. But it's really manure-powered! Crazy. From Cleantechnica:
Now poop power has made it to mainstream America with an announcement that the California State Fair will play host to the first known amusement ride powered by cow manure.
The Barnyard Animal Train will use excrement from California dairy cows to create renewable biogas. Kids taking a ride on the train will also have the opportunity to learn about renewable energy— and of course, will get to experience it firsthand.