Coincidentally enough (since we were just talking about this movie on Not-So-Gentle Reader, and by "we" I mean "some readers" and by "talking," I mean "were making fun of me for not having seen it"), I got the opportunity to watch Spoke Jonz's Adaptation, which is about "a lovelorn screenwriter [who] turns to his less talented twin brother for help when his efforts to adapt a non-fiction book go nowhere."
Let me get this out of the way, first: I would recommend you watch this movie. It's interesting and layered, and had I known a little bit more about the screenwriter who wrote it, I would have enjoyed it much, much more. (Here's what I would have liked to have known: Charles Kaufman is a real person. He is also a character in this screenplay. He does not have a brother in real life. You're welcome.)
While the one thing that stands out most about the film is probably the running thread of metadrama, art-imitating-life-imitating-art-etc., what I liked most about the film was the exploration of the creative process--specifically the writing process. Charles and his brother Donald have two completely different methods of approaching the blank page, both of which are valuable in their own ways. Charles' struggle to get his screenplay started pretty accurately represents what it's like to stare at a computer screen for hours waiting for inspiration. If you've ever tried to write anything, you'll identify with him.
For a little nugget of awesome from the film, here's a clip of Robert McKee (who's also, confusingly, a real person) giving a screenwriting seminar. Keep an eye out for the mistakes he mentions in the clip. I lurve that. (By the way, profanity abounds.)