Knock, knock. Who's there? Nobel. Nobel who? No bell, I knock.
Knock, Knock! Who's there? D umbbell. Dumbbell who? Dumbbell doesn't work so I had to knock!
Knock, knock. Who's there? Owls say. Owls say who? Yep, that they do.
Q: Why can't you tell blondes knock-knock jokes? A: Because they leave to go answer the door.
Knock knock. Who's there? Hatch. Hatch who? Bless you.
Knock-knock. Who's there? To. To who? No, to whom.
Knock knock? Who's there? Hitler! Hitler who? You Know, the man who kills jews.
Knock knock. Who's there? Urine. Urine who? Urine trouble if you don't open the door.
Knock Knock. Who's there! Ice cream! Ice cream who? Ice cream if you don't let me in!
Knock knock Who's there? Double. Double who? W!