Fridays I hang out with my three year-old granddaughter who has discovered knock-knock jokes. Here's the joke she told me today.
G-daughter: Knock, knock!
Me: Who's there?
Me: Apple who?
G-daughter: Apple poo-poo! (This is followed by uncontrollable laughter. Mine.)
At this point I think it's genetically hardwired in three year-olds to tell a) knock knock jokes that b) are scatological. Like, in France I'm pretty sure the kids would say knock, knock and their grandmothers would say qui is there and then the kids would say pomme and then their grandmothers would say pomme qui and then the kids would say pomme poo-poo and then I would start laughing uncontrollably again way over here in America.
Carry on, French kids!