The Nudge blog hit upon a Volkswagen-sponsored contest to find ways to use fun to change behavior. The winning idea might point toward a solution for Illinois' red light camera whining: speed past a traffic camera, and you pay a fine which goes into a pot. Obey the speed limit, and the camera enters you into a lottery to win the pot. A message sign flashes the pot amount as you drive lawfully by.
The speed limit: Stay within it to win it.