Oh boy let's see here.
There was a small short-lived fight club that was started my junior year in what was know as "the pit" (an underground hallway with the football team's locker room and meeting room).
One year there were a series of fights that broke out between a group of girls. (I learned how crowds form at alarming rates)
I was told a story by an English teacher that a few years prior the "senior prank" was to release thousands of crickets into the freshmen hallway. The chirping was still heard for about year afterwards. (Also the students hot caught because they bought all the crickets at the same pets store)
A girl in my class had sex multiple times with a janitor. (Not sure how it was found out but that was a thing that happened)
A super well known girl in my class and liked by everyone because she was just kind to everyone was getting love letters from a history teacher who was subsequently fired. He then started working at our local kohls and was getting recognized constantly so he then worked at a kohls in another city. (Sad story about the girl, she died in a freak snowmobile accident when she went snowmobiling with her boyfriend the year after we all graduated).
When I was a senior, senior pranks were not really a thing but a couple guys put icy-hot on the toilet seats and a friend of mine experienced it twice.
When we learned about faraday cages and how you can line the inside of bags to by pass those security things you find in stores and libraries my physics teacher thought it would be fun to see how many books we could steal from our library. (Since I worked in the library for a semester and played tennis the librarian loved me and basically let me do whatever and also excused me from her rules. So, there were no reprocussions).