Knock knock. Who's there? Ego.

Ego who? Eggoing to let me in, or is that just a waffle excuse?

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.

Knock knock. Who's there? No one.

No one who? Exactly.

Knock knock. Who's there? Anita.

Anita who? Anita little help with these heavy bags!