An initiative of Volkswagon, the Fun Theory says that fun is the easiest way to change people's behavior for the better. Volkswagen's videos show people using stairs painted like piano keys rather than standing on an escalator. Dropping items into a waste bin with funny sound effects rather than tossing the trash on the ground. Using a recycle bin with arcade effects rather than tossing bottles in the trash. These are very clever and very fun, wouldn't it be great if this idea spread around the world. See more of the video's here.
They also have a competition running until Dec. 15th 2009.
Find your own evidence for the theory that fun is best way to change behavior for the better. For yourself, for the environment or something entirely different. Your entries should be presented with a written explanation plus a visualization of the idea itself. It could be a simple sketch, photos or a film of a prototype. You decide what will do your entry justice. Check it out.