When a person is being nonsensical, dumb or, unpleasent we declare them from joketown. A place where all the "jokers" go. And/or when a serries of events happens in your life where you feel your life is a joke so you must be in joketown.
Francois, "Wow, did you just see that girl put a tampon in, in public."
Peneolope, "Yes, did. We must be in joketown."