Max:  How do we make him stop ?
Giles: I do n't know do something !
Max: Like what ?
Giles: Anything . What are you good at ?
Max: I can tell really , really good knock - knock jokes .
Giles: Ooh , let 's hear _ one _ .
Max: Knock - knock .
Giles: Who 's there ?
Max: Fanny .
Giles: Fanny who ?
Max: If anybody calls , I 'm out .
Giles: That 's even worse . You just made it even worse .