The glass armonica, invented by none other than Benjamin Franklin (working with glassblower Charles James), produces ethereal sounds from friction on a series of extremely delicate nested glass bowls, which form a keyboard.
Rob Scallon: "Nudge the instrument, glass shatters. Press it too hard, it doesn't play. Press it too soft, it doesn't play. You press the wrong speed, it doesn't play. You press it too hard, it shatters."
I has assumed one of my favorite pieces of weird music, Jacques Lasry's Manége (below), was performed on this instrument, but it turns out to be a more modern (and presumably more durable) descendant called a Cristal Baschet.