Dr. Knucklehead is knock-knocking at the door and children will happily answer, because they love knock-knocks—and these are the very best. Try this: Knock Knock. Who’s there? Daisies. Daisies who? Days he’s a man, but by night, he’s a werewolf! Or laugh a lot at this: Knock Knock. Who’s there? Billows. Billows who? Bill owes me ten bucks and he said you’d give it to me. Every one is riotously funny.