"Blood Libel" refers to the idea that a person or group of persons have been falsely accused of being involved in human sacrifice, ritual murder, and/or cannibalism. It is traditionally an anti-Semitic slur related to the myth that Jews used Christian children's blood in rituals. Oh, and Sarah Palin is pretty certain that everyone has been Blood Libeling her lately. Sorry 'bout the blood libel, SP! We'll all refudiate it as soon as we can figure out WTF you are talking about.