Everybody knows it. It's about a bunch of closefriends who, blah blah, oh well, ok, I will type it. They know each other for sufficiently long to tell the same jokes every time. So they numbered them, so that one could say "Joke 17" instead of the whole thing.
Next time, if you want to escape being told a joke you know, say "yes, joke #17". 17 is both the number of this joke and a random joke, for being the most random number.
Joke 17.1 is about one who laughs "oh, I haven't heard this before" and joke 17.2 is when one shouts "joke #800!" and gets a reply "shhh, why tell such rude stuff near women."
So, the time has come to build a global database. Please start by commenting to this post. The title should be a unique ID.