Knock knock. Who's there? Silence.

Knock knock. Who's there? Wendell.

Wendell who? Wendell you give in to the sheer pun-ishment of this joke and finally admit it's been weighing on you, a real heavy hitter in the groan department, making you wonder when 'til the end of this tale of wordplay woe?

Knock knock. Who's there? Flake

Flake who? Snow-body's home.

Knock knock. Who's there? A pause.

A pause who? No, just a pause. The joke's over.