Educational, at least (The Meddling Monk)
The Monk chooses a 1989 class, and takes the role of substitute teacher.
They think he's a bit mad (it's the eighties; he's wearing a habit) but enthusiastic, offbeat ways of teaching keep them interested. Just about.
So he announces a trip; they dutifully follow him into the bus (TARDIS). He claps his hands, as he leaps round the console.
He's surprised he gets them back home in time for dinner.
But didn't go back, after that - head of department, bit strait-laced – but, oh, how he hopes those silly humans managed to grasp some idea of their potential greatness.