R rated films as a whole have had a rough time making a mark on the market. A lot of that comes done to its limited audience that it can reach. The Hangover broke of conventions and was one of the top earning R rated films ever made. What makes The Hangover so intriguing is that it takes the standard trope of guys going on a man trip but instead of laughing at the shenanigans as they happen your laughing at what you havent even seen yet. Essentially following the story backwards, you learn the set-up of the whole trip and learn about all there discretions that have passed during their night in Vegas. Most of the jokes themselves are idiotic and simplistic, but the interaction within the group is what really adds the silliness to the whole story.