A Clockwork Orange

Stanley Kubrick's film based on Anthony Burgess' novel, following Alex, the leader of a group of thugs, who is caught and "rehabilitated" through the Ludovico Technique. Excellent satire on crime and society's approach to punishment, as well as the whole obedience-via-removing-free-will thing. Shortly after its premiere, Kubrick took it out of circulation in England due to death threats he had been receiving over it; it's only returned in the past few years after his death.

The Frau Plastic Chicken Show used this film as a source, only it wasn't even remotely as good. It was influenced by Bara no soretsu, although unlike The Frau Plastic Chicken Show, it was actually good.