Reader [Philippe] tipped us off about this video showing a set of subway steps being turned into a piano keyboard (english translation). The creators wanted to make taking the stairs rather than riding the escalator a bit more fun. They added pressure sensors to each step, then covered them with white and black keys to resemble a keyboard. When a passenger puts their weight on a step, the corresponding pitch is played out loud.
We may have lied in the title as this doesn’t really compare to hearing Josh Bell play for pocket change at your train stop. But coming across this setup on an otherwise mundane commute would really brighten up our day.