A joke that is composed of either an incredibly bad pun or a play on words. Named after the comical styling of David Chin of San Mateo.
ex. of a Kaj Joke-
Person 1: Ugh, I need a tissue. Does anybody have one?
Person 2: Who Nose??
Note that "nose" and "knows" are the words being emphasized as being the two interchangeable words, creating a hilariously bad joke.