oooh glass eyes
in the last show I played in before I left the UK, I was merrily playing along on my sax (I think it was The SUn Has GOt His Hat On, show was Me and My Girl) when there was a little ping as something hit my sax and landed between my feet
When I had a look, it turned out to be the glass eye belonging to an ancient old man in the front row.
QUite unnerving. but a good trick