Knock knock.
Who's there?
9/11.
9/11 who?
You said that you would never forget!
"Knock knock?"
"Mustache."
"I mustache you a question, but I'll shave it for later!"
"Knock" "Knock" "Whos there?" "aarghraawa"
Why did Sarah fall off the swing? She had no arms.
What did Sarah get for Christmas? I dunno, she hasn't opened it yet.
Knock knock...
Who's there?
Not Sarah.
Knock, knock. Who's there? An armless person. Why? They got stumped on why they contacted you.
Knock, knock.
Who's there?
Boo.
Boo who?
Don't cry, it's just a joke!
Knock knock. "Who's there?" "Grandma." "Oh, okay."
Nah, it's a penis.
Knock knock...... Who's there... not stephen hawking