The Fun Theory is an initiative from Volkswagens BlueMotion Technologies – a series of cars and innovations that help reduce environmental impact without compromising on performance or the joy of driving. This film is one of three experiments that prove that fun can change behaviour for the better.

The piano stairs: Can we get more people to choose the stairs over the escalator by making it fun to do? A staircase in a subway station was turned into a gigantic piano. The experiment was set up and secretly documented. Resulting in 66% more people than normal choosing to take the stairs over the escalator. The Fun Theory was proved.