Knock knock. Who's there? Accordion.

Accordion who? Accordion to the weather report, it's going to rain!

Knock knock. Who's there? Donut.

Donut who? Donut even think about leaving me out here!

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?

Knock knock. Who's there? Sew

Sew who? Sew long, I've been trying to weave a good joke together.