Knock knock. Who's there? Wheat

Wheat who? Wheat you waiting for, let me in

Knock knock. Who's there? Homer.

Homer who? Homer-ly, who could resist a classic like this? It's an *epic* pun, don't you think?

Knock knock. Who's there? Egg

Egg who? Egg-cuse me, I'm cracking under the pressure to make a good joke.

Knock knock. Who's there? The joke.

The joke who? The joke who was supposed to be original and unexpected, but now feels like it's just pointing out its own existence.