It just had to come out of the Netherlands. These contraptions, called the "Light Wind," are manufactured by Dutch design firm Demakersvan, and they're outdoor lights powered by wind. They might look like design-savvy variations on those little propeller beanie hats that I'm sure a few people over at the Googleplex have been known to accessorize with, but I personally think these are a cool "green" idea. They even have the capacity to store up energy when it's windy so that the light will keep shining all night long. (For size comparisons, the propeller is about two meters in diameter.)
Birds who like to perch on street lights, however, might disagree with me.