Volkswagen has started something they term The Fun Theory, which is "the thought that something as simple as fun is the easiest way to change people’s behaviour for the better." One way they've done this is by creating a giant piano out of stairs. There is an escalator right next to it leading to the same place, but that's no fun, is it? Take a look at this video:
Now I'm just waiting for someone to organize a flash mob around it.
Other things they've done is create a "speed camera lottery". Speeders get photographed and receive a citation. People abiding by the speed limit get entered into a lottery for a chance to win part of the money collected from said citations. That's definitely a lottery I would participate in!
