I know I've posted on here before, but...
In my GCSE Maths class there was a group of boys who constantly sexually harassed girls in my class- including me. It started off with them just making offhand comments but when they realised our MALE maths teacher wasn't stopping them it started getting worse, with the attempting- and often succeeding- of touching girls in my class. If you were sitting next to any one of those boys they'd try and stick a hand up your skirt (One girl started screaming when this happened, she got the detention for it.) and it wasn't just the 'ugly' girls getting this treatment, all the girls were getting it and every time we went and confronted our teacher about it he was all 'boys will be boys', 'just ignore them' and even 'maybe you shouldn't dress so provocatively'.
On the last day of the year I eventually snapped at those boys. I was sitting next to my boyfriend, we didn't have any work since it was the last day (We had to be in class though) so we were just chatting about the upcoming holidays, when the whole group of boys moved their seats around me and started trying to pull me away from my boyfriend. I started screaming, the teacher started yelling at me, the group of boys were laughing, my boyfriend started yelling at the boys... And then I punched one of the boys, square in the jaw. Everyone froze. All the girls started cheering as my boyfriend pulled me away, the teacher then sent me and the group of boys to the head teachers office. The boys tried to blame me, saying I lashed out at them. I wouldn't have any of it so I told the head teacher what had been happening for TWO YEARS without anything being done about it apart from the girls getting blamed.
All those boys lost their places at our local college and were not allowed to go to prom. Our Maths teacher was suspended. And finally the harassment stopped. (My boyfriend was not involved with that group of boys, just to fully clarify.)