Knock, Knock

Mason loves knock-Knock jokes, except he has little understanding of punch lines, and less of comic timing and delivery. His favorite one right now is:
Knock, knock. Who's there? Apple.

(repeat three or so times)

Knock, knock. Who's there? Orange. Orange who? Orange you glad I didn't say Apple?
A real scream, especially because he substitutes any and all fruit in place of orange and apple, not understanding orange = aren't in the joke.
Now Ashton has jumped on the joking bandwagon, and his version is to run up to you, yell "na-knock!" as loud as he can, and then laugh maniacally. I'm ready to knock their little heads together!!!