The X-rating has an interesting history in America that many people don't know about. It was introduced by the Motion Picture Association of America in 1968 to be applied to films featuring extensive sexual or violent imagery. But there was a problem. The MPAA did not trademark the X-rating, and it didn't take the porn industry long to begin applying it to their films - as a marketing ploy to play up a movie's sexual content.

The porn industry didn't stop there. They came up with their own XXX-rating, another attempt to woo jerker offers to their theaters. The MPAA lost control of the X-rating, and by the mid-70s it was almost completely associated with pornography rather than mainstream movies (remember that big movies like Last Tango in Paris, The Evil Dead, and Midnight Cowboy received the X-rating). So in 1990 the MPAA developed (and trademarked) the NC-17 rating to replace the X-rating, and the rest is history.

You guys loved our previous list of some of the best X-rated movies ever released, so today we're giving you five MORE X-rated movies that you simply need to see to believe. Something to note - the X-rating received such a bad rap in Hollywood that many films initially slapped with an X-rating were later edited to receive an R-rating. And some, like 1979's Phantasm, used industry connections to lessen a rating from X to R without having to edit the film. Whatever the case, let's talk about X, baby!