A chicken, a badger, and a narwhal cross the road to go to the library. The chicken realizes she forgot her library card. The badger turns to the narwhal and says, “Why did the chicken cross the road AGAIN?" The narwhal says…
Unfortunately, that's all we've got. We've been trying to come up with a good chicken/badger/narwhal joke for April Fools' Day, but we just can't seem to think of a final line that pulls it all together. What are we missing? The punch line, of course!
A punch line is the final part of a joke or comedy skit. It's the last piece of the puzzle that makes the joke funny or causes the audience to laugh. Traditional knock-knock jokes always end with a punch line.
For example, an old joke almost everyone has heard asks the question, “Why did the chicken cross the road?" The traditional punch line is “to get to the other side!"
As you can see from this example, a punch line is not necessarily funny by itself. “To get to the other side" probably won't make anyone crack a smile, but paired with the initial question, it will probably elicit at least a grin from most listeners.
Punch lines are often funny because they're unexpected. When most people hear the chicken crossing the road joke for the first time, they expect the answer to be something unusual and most definitely chicken-related.
That's why the punch line “to get to the other side" is humorous. It's unexpected in that it's so simple and also makes the chicken seem somewhat human by having the same motivations as the rest of us.
If you're wondering why it's called a punch line, so are etymologists. Etymologists are people who study the origins of words and phrases. So far, the etymology (origin) of punch line remains a mystery, although there are a few ideas about where it might have come from.
Some believe the term came about as a result of the fact that emphasizing certain parts of a speech is known as “punching up." In this sense, stressing the last line of a joke to “punch it up" for comedic effect might have led to that last line being called the punch line.
Sometimes, comedy sketches simply rely on the humor inherent in situations. Have you ever watched Mr. Bean? His comedy sketches have delighted millions for years, and he often doesn't have to utter a word!