Anyways, tlachtli was overall a brutal sport, rugby and American football have little on this sport. The game was played with a hard rubber ball (came right off of rubber tress) which became as hard as rock when temperatures dropped. Weighing anywhere from 5 to 10 pounds 2-5 players per team had to hit the ball with their elbows, hips or legs through a stone ring that was placed above the court typically several feet high.
The walls of the court it was played in were slanted So that the ball could make a feable attempt at bouncing off and helped the odds of getting the ball into the stone ring. The court was set up like modern volleyball, one team on one side and the other team on the other side. In some cases the game would go on for days with no break until one team got the ball through the ring to score a point.
The cultural importance of the game was huge to the Ancient Central American people because they would use the game for both weather predictions and as a form of human sacrifice. Priests and fortune tellers would study the path of the ball and they would create primitive forms of almanacs out of their predictions. Also at the end of the game either the winning team (the team that got the ball through the hoops the most) or the losing team would be offered to the ancient gods as sacrifice (the team to be sacrificed likely depended on the tribe such as Aztecs, Incas, ect).
Some modern artifacts remain from the ball courts. In fact a near completely-intact court remains today at Chichen Itza.