It's a known fact that knock-knock jokes will amuse a three-year-old for indefinite amounts of time. Seriously, the more incomprehensible the punchline, the harder they cackle. (Overheard in my van, between Micah and Julie when they were three: Micah: Knock, knock. Julie: Who's there? Micah: Tree. Julie: Tree who? Micah: TREE THAT LOOKS LIKE A HOUSE bwahahahahaha! They both dissolve in giggles. Then they repeat the same one, only switching roles. Repeat, ad nauseum, world without end, amen and amen. You get the picture.)
BUT DID YOU KNOW that a THIRTY-three year old (namely me) will laugh OUT loud, many times at a knock-knock joke? Only if it's this one, though:
Truly? If you don't laugh at that joke you may not have a soul. Check on that.