How do I get my revenge?

My two closest friends (plus a few others) just stabbed me in the back. They've done this before, and I've just let it slide after a day or two.. But not this time. I'm done. Now I just want to know how I can get back at them for making me go through all this crap. They've done nothing but ruin my entire middle school career, and I'm sick of it. So.. Please help? :) ?