Princess goes in & out of a Knock-Knock joke phase. It used to be a random word paired with another word, example: Chicken. Chicken who? Chicken fork
This occurred in the van not too long ago:
Princess: Knock Knock
Me: Who's there?
Me: guess who?
Pr: Guess we have to get some gas. Funny! Get it?
Gman: Knock Knock
Me (thinking "Great. Now I've got 2 kids telling bad knock knock jokes")
Princess: Who's there?
Gman: Funny. Get it?
Princess: No! It wasn't funny.