Girl and Boy are sitting together in their classroom, working on some math. Boy looks up from his paper.

B: Knock knock!
G: Who's there?
B: Ash.
G: Ash who?
B: Kazoontite!
[No reaction from Girl.]
B: Get it? The ash is hot like pepper and makes her sneeze!
[Still no reaction.]
B: Is that funny?
G: Yes.

Thank you Giuls!