There was a big discussion in our school district about bullying and how it is perpetrated by a very small percentage of students. What wasn't mentioned, and the biggest problem to my mind, is all the students who stand by and do nothing.
It reminded me of an incident when my son was in the 5th grade. He was staying after school to play basketball and I had just gotten there to pick him up. Another student had come to join in the game and he was a very overweight kid (my son at the time said he was "bulky"). The kids playing told him to go away, teased him and started throwing the basketball at him. I was about to head over and break it up when my son grabbed the ball and in a very commanding voice (especially for a 5th grader) announced "there is no reason he can't play with us; if you have a problem you can just leave now." There was a moment of silent tension followed by resuming the game.
My son was not a big or imposing kid, but he did know how to stand up for what's right. It was one of my proudest moments as a dad. I guess I shouldn't be surprised that he is a Sergeant in the Marine Corps now -- I guess standing up for what's right is just in his nature.