Computationally recognizing humor is an aspect of natural language understanding. Although there appears to be no complete computational model for recognizing verbal humor, it may be possible to recognize jokes based on statistical language recognition techniques. Computational humor recognition was investigated. A restricted set of all possible jokes that have wordplay as a component was considered. The limited domain of "knock knock" jokes was examined. A created wordplay generator produces an utterance that is similar in pronunciation to a given word, and the wordplay recognizer determines if the utterance is valid. Once a possible wordplay is discovered, a joke recognizer determines if a found wordplay transforms the text into a joke.