Eventing is commonly seen as a triathlon of the competitive equestrian world, due to the broad areas of competence required. The dressage phase (commonly held first) comprises a highly exact pattern ridden in a small ring. Rider and horse are judged on their ability to communicate with each other in performing prescribed delicate manuvuers.
The next phase, cross-country, requires both horse and rider to be in excellent shape and to be brave and trusting of each other. This phase consists of approximately 12-20 fences placed on a long (1-2 mile) circuit. These fences consist of very solidly built natural objects (telephone poles, stone walls, etc.) as well as various obstacles such as ponds and streams - anything that would commonly occur in the countryside. This phase is timed, with the rider required to cross the finish line within a certain time frame. Crossing the finish line either before or after the allowed time results in a penalty. Penalties are also incurred if the horse refuses to jump a fence or if the rider falls off.
The last phase, showjumping, tests the technical jumping skills of the horse and rider, as well as their fitness. In this phase, 12-20 fences are set up in a ring. These fences are brightly colored and consist of poles set in shallow cups. If the horse and rider are not in adequate shape or do not have the technical skill, then they will knock down the poles, incurring penalties. This phase is also timed, with penalties being given for every second over the required time.
The winner is the horse and rider with the fewest penalties. After the ribbons are awarded everyone gets to take a gallop around the ring. Then you go back the trailer and try to pull your boots off.