As a TA I f’ed with my students the first day. I planted my housemates in our tiered classroom, with one in the back row and one in the row below it. As I was writing my contact info on the board (yes, it was common then) the roomie in the back, on cue, knocked his pencil onto the floor and at the feet of the other roomie. The one in the back whispered to the other, requesting an assist with the pencil. I acted all perturbed, and when they tried to explain the situation I sent them out of the room. The real students’ jaws just dropped. I then continued writing on the board a note that the kids I sent out were my roommates - haha! They seemed to appreciate the humor.