Knock knock. Who's there? Cows go

Cows go who? No, cows go 'moo'

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? Figment.

Figment who? Figment of your imagination, but I'm real and I need to come in!

Knock knock. Who's there? Amos.

Amos who? Amos *astounding* fact about puns is that Amos *clever* one is Amos *likely* to make you *a-moan*!