Yes, EW has compiled a list (more or less in honor of Inglourious Basterds, not that the film is as graphic, but I digress) of 16 hard to watch movie scenes. The full list is here, but this is the quick rundown of the movies that contained these scenes:
A Clockwork Orange
American History X
Requiem for a Dream
The Hitcher (not the shitty remake)
The Last King of Scotland
Un Chien Andalou- aka An Andalusian Dog
-Irreversible is by far the hardest for me to watch...how about you?