Aren't spin glasses the musical instrument in which variously tuned glasses rotate on a sort of deck, and the musician, with appropriately resin-coated fingers, plays them by applying slight pressure to the edge?
[gil] That's a glass harmonica (as I'm sure you knew) - I always think "Playing the glass harmonica" sounds like a euphemism for something - not sure what though, perhaps it ought to be a Face Pyjama when !!York is reborn.