Commercial variant with pieces more suited to a war game: infantry, cavalry, armor, bombers, etc. From the site: "World War Chess is a chess-like military game for two players. World War Chess also demonstrates what could happen when two armies of equal size with equal abilities went to war on a chessboard on an alternating move by move basis. Each game piece represents a whole military unit and each square represents a different battlefield."
World War Chess: http://webpages.charter.net/wwchess/index.html