See You After School (2006) (KOREAN)

AKA: Rooftop After School
Genre: Comedy
Country: South Korea
Language: Korean
Cast: Bong Tae-Gyu, Ha Seok-Jin, Kim Tae-Hyeon, Jeong Koo-Yeon

The new boy accidentally gets on the wrong side of the high school bully, and is challenged to a fight after school.

Storyline:
Namkoong Dahl is a loser, constantly teased and bullied at school. He is transferred to a new school, where he reunites with an old friend who advises him to pick a fight on his first day so bullies will respect him. When Namkoong sees some bullies picking on a girl he likes, he seizes his opportunity. Unfortunately one of the bullies is the toughest thug in school. The bully challenges Namkoong to a fight after school - a fight Namkoong will do anything to avoid.

http://www.lovehkfilm.com/panasia/see_you_after_school.htm
http://en.wikipedia.org/wiki/See_You_After_School