The winning entry in the FunTheory.com contest is this one. The Speed Camera Lottery. Violators pay money into a pot. To qualify for the winning prize, don't speed. Interesting theory. Fun may be an exagerration, compared with many of the other creative entries in the contest on the FunTheory.com site.

FunTheory is a site is dedicated to the thought that something as simple as fun is the easiest way to change people’s behaviour for the better. Be it for yourself, for the environment, or for something entirely different, the only thing that matters is that it’s change for the better.