What most students of the art probably find the most enjoyable part is the sparring, or fighting one another. During special classes sparring takes place. This is probably the essence of TKD, in that you have to take what you have learned and put it all together against an opponent. You can practice fighting in class with pads on, so you can fix your mistakes and polish up your techniques if you are ever to use them elsewhere. Another major part that not enough people give credit to are the forms.
Forms are certain moves put together in a set of orderly steps.
For example, in the first form you start out turning to your left and blocking a low kick. Then different moves go on for another 20 steps or so. One of the requirements to pass a belt test is the memorization of your form. During the classes, students are taught a variety of different techniques ranging anywhere from a normal punch to a jumping, spinning crescent kick. It is a lot of fun to learn those fancy moves, even though it takes a lot of practice.