I'm completely enamored with 21 Obstacles by Daily Tous Les Jours. The project is a game projection installation, projected a building, with players using swings to interact with the game. The idea of using a swing as a controller is wonderful because it takes a usually relaxing, swaying motion and makes it energetic. Not only that, but the project begins to allow inhabitants of a region to have a loci of control over their environment, which one usually lacks in a city.

Link to the project.