Knock-knock Joke

The knock-knock joke is a type of joke, probably the best-known format of the pun, and is a time-honored "call and answer" exercise.

It is a role-play exercise, with a punster and a recipient of wit.

The standard format has five lines:

1. The punster: Knock knock!
2. The recipient: Who's there?
3. The punster: a variable response, sometimes involving a name (Doctor)
4. The recipient: a repetition of the response followed by who? (Doctor who?)
5. The punster: the punch line, which typically involves a pun-based misusage of the word set up during the response (How did you know?!)

Another example is: The punster: "Knock Knock!" The recipient: " Who's there?" The punster: " Boo!" The recipient: " Boo who?" The punster: "No need to cry, it's only a joke!"