The reason it made such a big impression on me is because I was 21 years old and NOT sober while I watched it. I loved it (the movie)
Another one is Pink Floyd's "The Wall", I only seen it sober, never F'ed up.
There was this really F'ed up movie I seen only one time, not all of it, and have never been able to find it since. I think the name of it was "Land Beyound the Valley of the Dolls", or something like that. I know there is a "Valley of the Dolls", and it deals with the party life in Hollywood, but thats not the one I'm talking about. This movie was one totally phsycodellic, tripped out flick.
There's animated movies like Fritz the Cat. Also check out Meet the Feebles. It's a completely twisted take on the Muppet Show. I mean seriously screwed up stuff, but it's still funny as heck. Give someone acid then drop in Meet the Feebles and tell them it's the Muppet Show 'Behind teh Scenes'