I recently bought a Japanese book titled 'すぐわかるアメリカンフットボール', or 'Quickly Understand American Football', for the lady of the house. While football does exist in Japan, it has one of the smallest followings and its rules are not well understood. I got this for her to prepare for her first live football game, which she will witness at Williams-Brice Stadium on November 11th.
すぐわかるアメリカンフットボール (Sugu Wakaru Amerikan Futtobooru)
So far she seems to be enjoying it, as she was testing me on penalty signals the other night. On the first page it explains that football isn't really a game played with a ball, rather it is a game of gaining / losing territory, and the ball merely serves as a marker for delineating this territory. I had never really thought about the game this way and found this explanation intriguing.