One that stands out was between a lad named "Groaty" and a boy David. David had the height advantage, but Groaty was a hard little p***k.
After an even first round (10-15 seconds) Groaty started getting on top and was just cracking David in the mouth continuously. David had braces, and on opening his mouth, it was clear to see that the braces had gone out of place and into his gums. He was an utter mess.
Eventually a teacher came steaming through to stop it, and David ran off lobbing himself over a fence to get away from the pursuing teacher.
Fights at school seemed to happen weekly when I started, but eventually calmed down. My Mrs is a teacher and hasn't reported any fights of late.