What are some comedy films with a unique premise?

I just finished Laughter in Paradise (1951) in which a practical joker who dies leaves a lot of money in his will to his relatives but only if each completes a specific assigned task that is opposite their own personality. For example, a quiet, respectable, retiring writer (Alistar Sims) must commit a crime that gets him 28 days jail (he is so proper that he gift wraps the brick to throw through a window). A unique or inventive premise goes a long way towards making a comedy a success and this movie spun around the difficulty people had doing something opposite their personality. 

What are some other comedies based on a unique or inventive premise? You don't need to explain the set up if you don't have the time- I'll look up the premise online. 

Thanks- I really appreciate it.