"Why did the chicken cross the road?" is a common
riddle joke. The answer or
punch line is: "To get to the other side." It is an example of
anti-humor, in that the curious setup of the joke leads the listener to expect a traditional punchline, but they are instead given a simple statement of fact. "Why did the chicken cross the road?" has become largely iconic as an exemplary generic joke to which most people know the answer, and has been repeated and changed numerous times.