In this episode of science project as advertising, Volkswagen turned the stairs at Odenplan subway station in to a piano stairs, which emits notes as you step on it. Suddenly it becomes a lot more fun than the old escalator and people used the stairs more often.
http://www.rolighetsteorin.se/en/ Is a site launched by DDB Stockholm for Volkswagen. The idea is that something that is made fun to do, is the easiest way to change people’s behavior for the better.
You know who else has a stair-piano? The Boston Science Museum.