I like checking each of the spots where you can catch people snogging during the evening. If it's a girl that I've made Jimmy kiss that day, I'll shoot the guy in the back with a slingshot. This then tricks the game into thinking that the guy hit the girl that he was kissing, so he gets all of the prefects on his arse.
I just like doing random crap in the game. Sometimes I'll instigate fights between the townsfolk and the students. I'll antagonise one of the adults into attacking me and then the other kids will just beat the crap out of the adults until the police come.
I also like hanging out in New Coventry (or is it Old, idk) and watching the Greasers piss off the townsfolk. One time, I saw Norton yank that old woman with the blue dress off of her scooter. Within 5 seconds, a cop had spawned and punched him off of the scooter, lol. It happened so fast, I didn't know what was going on.