God's Chinese Son: The Taiping Heavenly Kingdom of Hong Xiuquan

Semi-literate Chinese peasant hears a missionary preach, gets real sick, nearly dies, then is convinced that he has a vision that announces that he is Jesus' little brother, and that it's his job to purge China of their demon (ahem, the Manchu) oppressors. He then starts a revolt that ends with the slaughter of 20 million people. And that's just half the fun!