Jokes only a mother could love...

Ellie: Knock Knock.
Me: Who's there?
Ellie: Knock who.
Me: Knock who who?
Ellie: (silence, awaiting me to finish joke)
Me: Owls say, "Who who"
(Yeah I know I'm hilarious.)
Adam: Knock Knock
Me: Who's there?
Adam: Car
Me: Car who?
Adam: Banana, I named the car, Banana
Emma: Knock Knock
Me: Who's there?
Emma: Radio
Me: Radio who?
Emma: Radio not! Here I come!