From Treehugger. At TED David Cameron (apparently in an attempt to look like less of an ideological conservative) actually pointed out a really good idea to promote conservation.
On electricity bills just compare the user to their neighbors.
A commenter in the post mentioned that showing money saving would be a better incentive but why not show both?
People love to lord over each other how much better they are, or if you’re under-performing they like to know so they can comeback and beat their neighbors. it sounds silly but everybody loves to make a game out of things.
Head over there for the full post and a video of the talk.