Bunkasai

Bunkasai puts the player in the role of a male Japanese high-school student. One day his teacher tells him about the upcoming culture festival, giving him the assignment to help his lovely classmate Mia in the preparations. Naturally, the young man's mind is more directed towards... err... other aspects of Mia's personality. But what starts as a simple collaboration between high-school students soon turns into a drama full of violence and difficult decisions to make...

[From Moby Games]