A couple very obvious picks would be Eraserhead and Naked Lunch. Sorry I couldn't think of any more obscure ones at the moment.
Ah yes, NAKED LUNCH. "I can think of two things wrong with that title."

SPIDER is another Cronenberg flick that's pretty out there.
Not a bad movie per se, but VALHALLA RISING is bizarre.
IN THE MOUTH OF MADNESS is pretty weird, very Lovecraftian though not based on any specific Lovecraft story (I personally love it but it gets a lot of flack)
I suppose you could call VAMPYROS LESBOS arty.....
