A friend of mine, a professional organist, was asked to play for a wedding. Unfamiliar with the church's organ, she went to the sanctuary to practice.
Curious about a small keyboard that slid out from under the two regular keyboards, she tapped out a couple of bars of a children's song but heard nothing. Then she played a few more notes, but still no organ music.
Just then a man came running into the church, shouting, "Who's playing 'Three Blind Mice' on the church-steeple bells?"