ROLLERBALL (1975)
It's sometime in the near future. The world is ruled by industrial cartels (Energy, Luxury, Transportation, etc.), headed by Executives who make all the decisions for people. Aggression is confined to the game of Rollerball, an ultra-vi form of roller derby. Houston (Energy) is the champ team, captained by Jonathan E (James Caan), impassively brutal on the track but seemingly wimpy off track (you have to lean into your TV to hear him). Executive bigshot Bartholomew (John Houseman) wants him to retire, but Jonathan won't obey--he holds a grudge because an Executive took away a "wife" assigned to him that he loved. The Execs can't just kill Jonathan because he's too popular. So, they remove all rules from Rollerball, hoping he'll be killed in the game.
The plot isn't very complex, and Caan, as Jonathan, isn't a very sympatico character. But, the action, though brutal, is outstanding, and the filming is superb. Worth watching.