Fun fact: well-liked middle school bullies often turn out to be drugged-up high school losers.
If the school authorities won't punish a student based on extracurricular activities, you either get your parent(s) to repeatedly threaten the school with legal action (they hate that!) or contact the parents of the kid. Start documenting what bullies have done, complete with dates and times. Include names and pictures of injuries (or muddy homework). If you're ever seriously physically beaten, call the police and charge that student or group of students with harrassment.
However, if you think this will lead to more bullying at school... Inform your teachers of the bullying for sure, just to let them know what's going on in your life (they really do care), and maybe even make an effort to bond with them, if possible.
Another option -- and this isn't a personal attack! >.> -- address a superficial reason for which they're bullying you (other than their own inadequacies) and, if it's changeable or you don't mind giving it up, change it. For example, I had a good friend who was picked on relentlessly for dressing 'goth', and while she could easily break their noses in defense, she just stopped wearing those clothes to school, though she still wore them on weekends. The bullying continued, but it was certainly less intense, and it was really silly to watch them try to find other things to make fun of. (They told her her hair was 'too long' - wtf? Middle school is ridiculous.)
As for me, I rode it out. Some of it was more intense than others (punches to the gut for countering an insult -- ow), some simply damaging (someone loudly daring another to ask out an ugly girl, and minutes later I'm confronted by a giggling, acne-ridden football player), but one year I cut my messy hair short and just started laughing things off. It stopped soon after that. Laughing really does help, or commenting on what they've said or done with a lighthearted attitude. It doesn't even have to be clever.
I've also heard that just telling a bully to stop is pretty effective. Or just saying, "Well, I've had enough" and moving away, as if what a bully is doing is beneath you. It apparently worked for another friend (all my closest friends were at one point outsiders xP).
Sorry for rambling. XD I can't stand bullies, and middle school is terrible enough without them. I'm glad you don't have long before high school; most people, after a few weeks in, seem to realize, "Hey. I'm really effing dumb," and it gets so much better from there.
