A guy walks into a bar and sees a group of people. One of them says a number and the rest laugh. Then the next person says a number and everyone laughs again.
"What are you doing?" he asks them.
"We're telling each other jokes, but since we keep telling the same ones, we've assigned each a number and rather than telling the whole joke all over again, we can just reference it quickly that way"
"Can I try?"
"Sure, go ahead"
"42", the guy says.
Everyone starts laughing and laughing and won't stop.
"What did I say?"
"Well you see, the joke you told us was:
A guy walks into a bar and sees a group of people. One of them says a number and the rest laugh... etc. etc."
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In the original joke the last answer was simply "We hadn't heard that one before", but I'd like to think my recursive version has more depth to it.