You study these things on fixed forms because it is easier to analyze and understand what is going on. But the extension to general joke-making is straight forw

You study these things on fixed forms because it is easier to analyze and understand what is going on. But the extension to general joke-making is straight forward, provided you have working NLP (a big if!): data-mine the concept graph for thoughts/memes which have similar structural content but surprisingly (in the technical sense) different meanings, then construct a sentence that maximizes probability during reading of the first interpretation but ends with the second. This captures basically all humor from puns to "I like my X like I like Y: Z" to most forms of stand-up comedy.