Neatorama has recently featured Bach's Toccata and Fugue in D Minor, played on floppy disk drives. Several years ago we showed the piece played on an accordion. But we somehow missed this version, played on a glass harp. The instrumentalist is Robert Tiso.
Wow.
What you're probably thinking of is a "glass harmonica."
http://www.youtube.com/user/dragonflye?feature=mhum#p/a/u/1/wfLj2ePIjgU
As it happens, I have a post on my own blog about the glass harmonica (with links to sound samples):
http://emilyd47.blogspot.com/2011/01/glass-harmonica.html