Knock knock. Who's there? Wu

Wu who? Wu don't know, I'm having an identity crisis!

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*!

Knock knock. Who's there? Fig.

Fig who? Fig-ure it out yourself, I'm busy!

Knock knock. Who's there? The sound of one hand clapping.

The sound of one hand clapping who? Exactly! You're not supposed to be able to answer that.