Person 1: Did you hear the joke bout 9/11?
Person 2: No, but it'll probably crash and burn.
Alright, listen up, buttercup. This joke is about 9/11, which you should know was a super tragic event when some bad guys crashed planes into buildings. The punchline is "it'll probably crash and burn," which is like, duh, because that's exactly what happened. It's funny 'cause it's dark and you're dumb.