A Zoë original...

Zoë: Knock, knock.

Mommy: What? Did you just say "Knock, knock"?

Zoë nods.

Mommy: Oh, uh, Who's there?

Zoë: Blue.

Mommy: blue who?

Zoë: Bluuuuuuue.

Mommy: Uh, okay, blue who?

Zoë: No, bloooooooooooo. (with wiggling fingers and ghostly changes in pitch)