Piano stairs - The fun theory

So it seems these guys rigged a subway staircase in Stockholm next to the escalator with sensors creating the noise of piano keys hoping it would get more people to actually bend their knees by making it fun. Their idea actually worked, here's what they had to say ''We believe that the easiest way to change people's behaviour for the better is by making it fun to do. We call it The fun theory''. Check out more of their fun vids on their website http://www.rolighetsteorin.se/