For the ZX Spectrum. You played Eric the schoolboy who was confined to an endless round of lessons, breaktimes, assemblies, etc. The fun to be had was to create trouble without getting caught by one of the teachers (Mr. Withit, Mr. Creak, etc.) who would give you lines. The school swot Einstein would also be on hand to grass you up in lessons ("Please sir, I cannot tell a lie, ERIC hit me!") unless you thwarted his progress by continually pushing him off his chair. Angelface the bully was another character, who would throw punches from time to time. Once you had accumulated 10,000 lines, the game was up and the headmaster would come and find you and expell you from his school, which was on three levels and well-rendered for a 48K game.
The follow-up, 'Bak 2 Skool' expanded the theme by giving Eric more to do, and adding a playground and a girl's school, with a heroine who would eradicate some of your lines if you snogged her. My favourite trick in the sequel was to fill up the cups on the high shelf of the ground floor of the school and knock them onto the passing teachers with a catapult, who, if you timed it right, would shout out a number, which was part of a combination which (once you had them all) released a bicycle which up to that point had been parked against a tree in the school yard. The lines I got riding that in the school itself were many!