Trivia: Prior to the release of this film, Johnny Knoxville was reported to be, by an American tabloid, "so dishevelled" by a boy who died reconstructing "Big Wheel Craze" that he refused to make the movie or any more episodes of "Jackass." Two weeks later, the ad for the film was shown in the exact same spot in the paper.
Trivia: Around the time of the movie's release, the creators and studios behind the "Jackass" franchise were sued by a man who had legally changed his name to "Jack Ass" in the 90's to raise awareness of drunk driving. Mr. Ass (don't laugh) sought over $10 million in damages, claiming that the franchise would ruin his reputation, but the case was eventually tossed out by the court, presumably because "jackass" is a very common word.
Chosen answer: It's Carl Orff's classic composition "Carmina Burana". It's most prominent use was in Excalibur (1981), other movies to feature it include Detroit Rock City and General's Daughter (both 1999).