Every year in IB Film we do a unit on The Hero's Journey based on the ideas that Joseph Campbell proposed in The Hero with a Thousand Faces and popularized for storytelling strategies by Christopher Volger in The Writer's Journey. I find it really helps the students both analyze the structure of the film and discover how the plot ties into the theme. Usually we read a chapter from The Power of Myth, a transcript of Campbell's conversation with Bill Moyers about Mythology.
Always looking for new material to supplement the lesson, I found this great comprehensive explanation of the whole journey in a few minutes from TED Education.