The Longest Yard was the answer that popped into my head, I love that movie. I just read they are re-making it (which I think is wrong). I also loved Radio if you consider that a football movie.
Right away The Replacements popped into my head as my favorite football movie. Why you ask? Well, it was a good enough movie, interesting, but mainly because it starred my absolute favorite -- Keanu Reeves. All my friends laugh when I say this, but I just love him.