(Spoiler Alert: If you've never seen the movie Fight Club, don't read any further. It's ridiculous to say that about a movie that's ten years old, but you know how people are.)
This morning, my son asked me if I'd heard the theory that Ferris Bueller and Cameron are the same person, ala Fight Club. I hadn't, but he told me more about it and I'll be darned if it didn't make at least a little bit of sense. A few hours later I stumble across a similar theory about What About Bob? I doubt that either movie was originally written with that in mind, but like the Wizard of OZ/Dark Side of the Moon phenomenon, if you put in a little effort you can make them fit.