Sometimes eeeevil corporations (aren't they all eeeevil?) give a green light to cool ideas, so let's give it up to Volkswagen for their The Fun Theory award - the idea being that if you make something more fun, they will be more inclined to do it.  Even if it's good for them.

The link above has lots of fun theories on the environment, healthy, behavior, etc. but in the meantime check out this clever way they get sloths in Stockholm to take the stairs!