Watching a film in school theatre (felt like an actual movie theatre, really good quality), my friend was in the row behind me and was poking me and making stupid noises to irritate me. So next time he tried to poke me in the back of my head, I grabbed his forearm and pulled him from his seat over my head and onto the ground in front of me. Slapped him in the face to make him feel stupid, then he went scampering back to his seat and didn't bother me again. It felt very satisfying. Didn't get in trouble because it was noisy and the teacher was in the front row.