Satyricon (1969)

Satyricon is difficult to describe.  It's strange, but not exactly alienating.  It follows the bizarre and often sexual adventures of a young Roman man and his frienemy.  It's taken from an ancient book by Petronius that has only survived in fragments, and so the plot itself is very fragmented.  It's not always clear how one scene leads into another, and the movie ends in mid sentence.  (Which I think turns out to be a nice metaphor for life.)  It can be hard to find, but I highly recommend watching it.