In ancient times, the Roman games--that heady cocktail of mass slaughter, gladiatorial combat, and chariot racing--made strong political, social, and cultural statements. The Roman emperor Commodus wanted to kill a rhinoceros with a bow and arrow, and he wanted to do it in the Colosseum. Commodus's passion for hunting animals was so fervent that he dreamt of shooting a tiger, an elephant, and a hippopotamus; his prowess was such...