In the Star Trek episode "A Taste of Armageddon," Capt. James T. Kirk and crew beam down to planet Eminiar VII against the wishes of its government to find what appears to be a peaceful, highly advanced civilization. In reality, however, the planet has been at war with a nearby planet for over 500 years, suffering the loss of up to 3 million inhabitants annually. They have managed to continue functioning as a society by conducting their war entirely by computer. The computer on one planet fires virtual salvos at the other planet, whose computer in turn selects individuals who have been deemed casualties of the war. Those individuals are then ordered to report to disintegration chambers, whereupon they are vaporized. The citizens of both planets seem to accept this as their patriotic duty, for they do indeed report to the disintegration chambers when so ordered. In this way the bloodlust of both planets’ governments is satisfied while their civilizations are spared the destruction caused by bombs and bullets and are therefore able to maintain the veneer of civil society.

http://original.antiwar.com/mike-tennant/2010/02/02/neat-painless-perpetual-war/