Leonardo da Vinci, in between doing stuff like painting the best-known piece of art in the world, apparently had time to sketch up a quick blueprint for an instrument: the "viola organista," a piano-violin hybrid that he never built. It looks just like a piano, and plays like one, too, but instead of the hammers that connect to strings and play notes, cranks wrapped with horse-hair like violin bows rub the strings. The resulting sound is familiar but strange, something like a church organ that's just a little on the tipsy side.