Knock, knock.
Who’s there?
Joem.
Joem who?
Joem Ama.
Listen up, buttercup. This joke is a play on words. The setup is a classic "knock-knock" joke. The punchline is "Joem Ama" which sounds like "Joe Mama." It's funny because it's unexpected and makes you look like a fool for saying your own momma's name.