Nope, but here's one for ya: My friend and I have an inside joke, just between the two of us. (She's a few years older than I am). We heard a joke a while back about two old ladies who can't remember anything, and the punchline was "How soon do you need to know?"

So now whenever one of us asks the other a question, instead of saying "I don't remember", the other one will respond "How soon do you need to know?"

But here's the good part: Both of us can remember the punchline, but neither one of us can remember the joke.