My husband told me about the Fun Theory from Volkswagon which takes environmental tasks like throwing away litter or recycling and adds unexpected interest to them. Like making a set of public stairs that are unused (thanks to the escalator next to it) into a piano and gaining 66% more stair users.
From their website: "This 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 something entirely different, the only thing that matters is that it’s change for the better."