Knock, knock. Who's there? Nobel. Nobel who? No bell, I knock.
Knock, Knock Who is there? A long erected penis with an eye on my head and some wools in my feet. What do you want? Is there any body to suck me? I want to weep.
Knock, knock! Who's there? Spell. Spell who? W-H-O.
Knock Knock! Who's there? Justin Justin who? Justin time for dinner!
Knock Knock! Who's There? Figs Figs who? Figs the doorbell, it's broken!
Knock, knock. Who's there? Kanga. Kanga who? Actually, it's kangaroo!
Knock Knock. Who's there? Opportunity. Don't be silly - opportunity doesn't knock twice!
Fast way to screw up someone's Knock Knock joke...? "It's open."
Chuck Norris was once part of a knock knock joke. The Joke ended abruptly when after the first knock the door blew up killing the man behind it.
"Knock, knock.Who's there?" very long pause... "Java."
Knock knock. Who's there? Sarah. Sarah who? Sarah problem here?