TAKE A DRINK...
-If Ian Gillan forgets the words & starts making up his own
-If they rhyme a girl's name with something, 2 drinks if it's "Nancy" and "fancy"
-If the song is about some chick
-Every time Ian Gillan makes an exclamation like "Yeah!" or "Oww!"
-Whenever Ian Gillan starts talking to the audience
-Every time you hear a line you just can't make out the words to, 2 drinks if no one else in the room can figure them out either
-When Ritchie Blackmore conducts himself (you can't hear this when you listen, but it's there)