The joke:
NASA named a rock on Mars for the legendary band the Rolling Stones. Scientists said they did it because the rock has the same age and density as Keith Richards’s liver.
How I wrote it:
At first I focused on this news item because it was interesting. And if a story interests me, it’s likely to interest many other people, which makes it a top candidate for being a joke topic. The news item also seemed promising because it has a couple of handles with many associations.
So I turned to Punch Line Maker #1: Link two associations of the topic. One topic handle, “rock,” has the association “hard.” The other topic handle, “the Rolling Stones,” has the association “Keith Richards,” who is associated with “alcohol abuse.”
I realized that I could link “rock-hard” to “Keith Richards’s alcohol abuse” with the idea of his rock-hard liver. Is Richards’s liver really as hard as a rock? No, but my Joke Maximizer #8 is “Wildly exaggerate.”
Finally I had to add an angle to the joke. “Scientists said they did it because the rock is as hard as Keith Richards’s liver” would have worked okay, but most rocks are hard, and my Joke Maximizer #9 is “Get specific.”
So I considered the more specific handle “a rock on Mars,” which in addition to being hard is also very old, an association it shares with Keith Richards and his liver.
I combined the ideas of “hard” and “old” in the angle “Scientists said they did it because the rock has the same age and density as…” Because that angle exploits two links between the topic handles instead of just one, it makes the joke a little more surprising and therefore funnier.