A friend of mine was playing a gig with his band at the Pike Place Market in Seattle. The guy who throws fish was shouting out "Play some Sabbath" after every song. Finally my friend said, "Ladies and Gentlemen, the man who throws fish for a living will now sing Iron Man. Lets all help him out." Then the aduience started doodling out the riff to Iron Man, but the man who throws fish was too embarassed to sing.