Dog Poop Lights Park Lamp

A dog park in Cambridge, Mass., is being lit up by the excrement of the dogs who visit, reports Fast Company. Dogwalkers are encouraged to deposit their pets' waste at a methane digester called the Park Spark, which then turns into a burnable gas that powers a lamppost. The team behind the project hopes the park will be busy enough to power other objects, like popcorn stands or projectors for community events.

"The digester will never generate enough energy to power, say, a whole block of streetlights, but that's not the point," writes Ariel Schwartz. "If Park Spark can demonstrate to community members that waste is a precious resource, it will have fulfilled its goal." (More energy stories.)