It's a loose retelling of Homer's Odyssey. I didn't pick up on it until Big Dan, the one-eyed Bible salesman (played by John Goodman), attacked them with a club that he broke off of a tree. When I re-watched it a few years later, I saw a lot more similarities, in particular that George Clooney's character Everett was named Ulysses Everett McGill. It was well worth the re-watch.
I'm not anti-Christian. I'm anti-stupid.