Ulama is a game that descended from the Aztec version of the Mesoamerican ballgame, the game is one of the oldest continuously played sports in the world, and is also notable for the fact that it is the oldest known game utilizing a rubber ball. (Wikipedia – http://en.wikipedia.org/wiki/Ulama_(game))
The ball, or ulli, was made of hard rubber and weighed about 9 pounds. (http://www.aztec-history.com/aztec-ball-game.html)
References:
Wikipedia – http://en.wikipedia.org/wiki/Ulama_(game)
Aztec Ball Game – http://www.aztec-history.com/aztec-ball-game.html
Photo – http://aktuelresim.com/Image/763131_ulama