Every year, as in many cities, Geneva organizes the Fête de la Musique. It brightens the city with 3 days of free music and dance in a wide variety of genres. For Geneva it more or less indicates the start of the summer. What's even more fun though is the inclusion of Street Pianos that anyone is allowed to play. While occasionally there are those of whom you'd wish they didn't touch it, more often than not the result is a surprising amount of fun.
Easy you say? You try hitting the money note over and over again.