While the phrase "rated X" likely conjures up images of the kind of movie to which Travis Bickle might squire a date, the rating's original intention had little to do with the pornography that eventually came to define it. When the Motion Picture Association of America (MPAA) decided to implement a ratings system in November 1968, its purpose was to easily communicate to parents whether a flick would be fun for the whole family… or earn them a visit from child protective services.
But it didn't take long for the adult industry to join the party and co-opt the salacious-sounding X -- then take it two steps further by adopting a XXX rating for its spiciest titles.
Because the MPAA neglected to trademark its ratings system (opening the door to that aforementioned porn penetration), rather than compete with or take on the adult industry to bring the X rating back to its original purpose, they dropped it altogether.
In 1990, the X begat the NC-17 rating -- though some filmmakers have opted to distribute their movies with no rating at all (the ratings system was, and is, voluntary). We pored through each group -- X, NC-17, and unrated -- to create an adults-only celebration of movies for grownups. They may not all be masterpieces (hello, Showgirls), but even a guilty pleasure is called a "pleasure" for a reason. Here are 50 great X-rated (NC-17-rated and unrated) movies to add to your viewing queue.