Movies that push the envelope...
Hardcore movies, in every sense of the word, always fascinate me so what movies have you seen that make you step back and say "That is going way too far..."?
Sounds like Ichi the Killer is making some waves, and there's that August Underground from a while back.
In the Realm of the Senses, made back in the final days of the sexual revolution cinema and before pornography got really dilluted, is probably the most sexually explicit movie (not including just straight-up cheesy porno) I've ever seen. The movie doesn't go two minutes without nudity or sex, which gets more and more grotesque as the movie goes on.
Then there's Salo: The 120 Days of Sodomy, made by Pasolini (he's made some good movies, though he's relatively minor in the arthouse and foreign circut) as his final farewell to cinema. People still are calling it the most disturbing movies ever, and I hear there's an insane amount of torture going on, such as tongues get pulled out and hungry rats getting hung from a woman's vagina. I haven't seen it myself since the Criterion DVD (probably the only uncut US release) goes for upwards of $300.