The first movie I literally ever made in my life was about two guys playing Stratego with each other. I had all my friends dressing up like the military characters in the game. So 'Battleship' is really my second board game turned movie!
I believe that anything in this world is fair game for a creative exercise.
There's a picture of the real Coach Gary Gaines in the book and he's sitting in the locker room after a game, and he just looks so much like Billy Bob, that we went to him.