I am not sure if everyone was aware of this or not, but there will be a film adaptation of "The River Why" coming out next year. And if you have not read the book yet, I recommend that as well.
I hadn't heard about the movie until I saw the headline for the article on the home page of this site. I'd think it would be a difficult novel to make a movie of. For one thing, a novel is too long and complex for an hour and a half telling. I think short stories and novellas make better movies.