Knock knock. Who's there? Vaughn.

Vaughn who? Vaughn voyage! Hope your journey's ship-shape and full of bon-bons!

Knock knock. Who's there? Wanda.

Wanda who? Wanda why you won't open the door!

Knock knock. Who's there? Maple.

Maple who? Maple syrup to talk to someone, I'm feeling a little drained.

Knock knock. Who's there? A philosophical question.

A philosophical question who? If a joke falls flat in the forest, and no one laughs, was it ever funny?