Knock, Knock...

We recently endured this gem of a Knock Knock Joke.

Son: Knock, knock.
Dad: Who's there?
Son: Banana.
Dad: Banana who?
Son: Knock, knock.
Dad: Who's there?
Son: Banana.
Dad: Banana who?
Son: Knock, knock.
Dad: Who's there?
Son: Banana.
Dad: Banana who?
Son: Knock, knock.
Dad: Who's there?
Son: Banana. Orange. Aren't you glad I didn't say "Banana" again?

Source

It's all in the delivery. Wow. =D