Gakuen Heaven: Nakajima-hen
学園ヘヴン 中嶋編
This version of Gakuen Heaven follows the same period of time and events as the original Gakuen Heaven anime, as well as the alternative versions of the manga, but changes the story enough so that Nakajima is the one who wins Keita Itou's heart.
A more complete description of the common story can be found under Gakuen Heaven (manga).