3 year old humor

The Sproglette has started telling jokes. Mostly they make no sense at all, like this classic.

S: Knock, knock.
Me: Who's there?
S: Door knob.
Me: Door knob who?
S: Door knob on the door is broken!

Then she laughs hysterically for 5 minutes at her great with and she then starts a new one.

This morning, she took off on the chicken butt joke.

S: Mommy, guess what?
Me: What?
S: Chicken butt!
(I have a completely surprise non-fake laugh at this one - I didn't know she had heard the chicken butt joke)
S: Guess what?
Me: What?
S: Kangaroo butt! Guess what?
Me: What?
S: Baboon butt! Did you know they turn red, Mommy?
Me: Yes, they do, don't they?
S: Yeah - but only when it's "making" season.
Me: Making season?
S: Yeah - YOU know - when they want to make baby baboons! Silly Mommy! Guess what?
Me: What?
S: Elephant butt!
Me: Wow - you know a lot of these jokes, don't you!
S: Mommy, I got a million of 'em!