Knock knock. Who's there? Sue

Sue who? Sue-per excited to meet you, it's a shoe-in for a new friend!

Knock knock. Who's there? Cows go.

Cows go who? No, cows go 'moo'.

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? Silence.