The other night Karen and I were sitting in the living room with our 4-year-old son, Finnden, recounting the high-points and low-points of our days. As Finn shared his low-points he kept making terrible grimaces and pouty-faces.

I said, "Finnden, let's be happy about something instead. Maybe you should tell me joke."

He stared at me blank-faced for a moment and asked, "What's a joke?"

He didn't know what a joke was! I'd never considered the idea. At what point does a person learn what a joke is? Or how to tell one?

He asked again, "What's a joke?"

"A joke is a little conversation or a story you tell someone to make them laugh."

"Okay," he said, clearly expecting me to proceed doing just that. The trouble is I couldn't think of any jokes. That is, I couldn't think of any jokes other than knock-knock jokes. I ended up deciding that maybe knock-knock jokes were a good place to start. Pretty fool-proof... or 4-year-old proof. So I began.

ME: Knock-knock.
FINN: (blank stare)
ME: You say, "Who's there?"
FINN: When?
ME: After I say, "Knock-knock." Okay, again. Knock-knock.
FINN: Who's there?
ME: Orange. (pause) Say, "Orange who?"
FINN: Orange who?
ME: Orange you glad I didn't say "banana?"

Karen laughed. So Finn laughed to be in on the fun. He clearly didn't get it. I tried another one.

ME: Knock-knock.
FINN: Who's there?
ME: Interrupting cow.
FINN: Interrupting...

Karen laughed harder. Finn laughed harder because it seemed like the thing to do.

I told him he should tell one of the jokes to mom, so he turned to Karen and began.

FINN: Mommy, knock-knock. Who's there?
KAREN: No, I'm supposed to say, "Who's there?"
FINN: Then say it.
KAREN: Start over.
FINN: Okay. Knock-knock.
KAREN: Who's there?
FINN: Orange.
KAREN: Orange who?
FINN: Orange cow. MOO!

Karen and I fell apart laughing. We were crying. Finn was laughing, clearly thinking himself a better joke-teller than daddy. It was several minutes before we began to recover, panting from having laughed so hard.

Then, Finn turned to me.

FINN: Hey daddy!
ME: What?
FINN: Why did the snake take a nap next to the ruler?
ME: (wondering where this might be going) Er...I don't know. Why?
FINN: He wanted to see how long he laid down.