Do you ever wonder how something becomes a Thing? I wonder about it all the time. How did knock, knock jokes become a Thing? Can you imagine the first person to tell a knock, knock joke?

“I’m going to say, ‘Knock, knock,’ and you say, ‘Who’s there?’ OK?”


“You’ll see.  Just do it.”

“But you’re standing right here.  Why should I ask, ‘Who’s there?'”

“C’mon.  Please?”

“Will you stop pestering me if I do it?”



“Knock, knock.”

“Who’s there?”


“Why are we doing this?”

“No, you’re supposed to say, ‘Lettuce who?'”

“I don’t understand.”

“Just say it.”

“Is Lettuce someone’s first name?”

“Come on.  Just say it.”

“Do I know more than one person named Lettuce so I need to ask which one I’m talking to?”

“You’re thinking too much.”

“Will you stop pestering me if I say it?”


“Lettuce who?”

“Lettuce in, it’s raining.”

“That was a whole lot of effort for nothing.”

And yet, all it takes is for someone to say, “Knock, knock,” and everyone automatically says, “Who’s there?” How did that become a Thing?