The reason limericks are so much fun is because they are short, rhyming, funny, and have a bouncy rhythm that makes them easy to memorize.
The Rules of Limericks
They are five lines long. Lines 1, 2, and 5 rhyme with one another. Lines 3 and 4 rhyme with each other. The first line usually ends with a person’s first name or the name of a place. The last line is usually funny.