The Kid woke me up this morning with an idea for his own version of D&D: Creatures and Classrooms. Monster-Teachers try to bore you (costing you Fun Points), and the students try to wear down their teachers with pranks until they retire.
Follow up: The kid took his rules into school, and has started up a game during "Centers" time. Three days in, and it sounds like things are going well—the players have discovered that the Teachers are aliens with a vulnerability to water, and have armed themselves with water guns. "I think I'll take them to Mars, today," he said at breakfast.