Teaching My Kids to Turn Off The Lights

With four kids, we are in and out of the house all day long -- it is a constant struggle to try and keep lights turned off and save energy. I've tried talking to the kids and letting them know how much money and energy we are wasting by leaving everything running when no one is home but nothing seems to resonate with them. I am hoping that the GreenHomeSource community can step up and give me some creative ideas to get my kids excited saving energy and turning off the lights when they leave a room!