In this technique a word, or a prefix, or even a few letters are added to an existing word or phrase to create an incongruous meaning.
Woody Allen, "These people were really hip. They were sitting around in black turtlenecks, drinking pre-Columbian coffee."
Adding "pre" creates the joke. We know "Columbian coffee" (known phrase) and "pre-Columbian" refers usually to a style of art. Allen combines the two concepts creating a brilliant line.
Add-a-words create easy incongruities:
Lincoln Log Memorial
Toy train schedule
Liquid paper route
The forumla: Take a well-known phrase and add a word or prefix to get the laugh.
Woody Allen was greatly influenced by the works of S.J. Perelman. Some of Perelman's best jokes will be analyzed in the next lesson. Stay tuned, sports fans.