Knock knock. Who's there? Nobody.

Nobody who? Exactly. Why are you talking to the door?

Knock knock. Who's there? Otto B.

Otto B. who? Otto B. a crime if you didn't laugh at that groan-worthy pun!

Knock knock. Who's there? Isadore.

Isadore who? Isadore a lock on this door, or is it just glued shut?

Knock knock. Who's there? Amos.

Amos who? Amos *astounding* fact about puns is that Amos *clever* one is Amos *likely* to make you *a-moan*!