What's Your Favorite Underappreciated Movie?

Moses Lawn asks: "With the impending re-release of Spirited Away, I've been wondering about this. There are a lot of movies I love that no one else seems to know about. Some of them disappeared from theaters within a week, some came out years ago and seem to have been forgotten. Here are a few of my favorites: The Hot Rock, The Pope Must Diet (formerly 'The Pope Must Die'), They Might Be Giants, and The Big Hit. Maybe you like these, too. Maybe you think they stink up the joint. So what are your favorite forgotten movies?"