Oh, yes, one of the things a friend of mine did, was that he brought a porno dvd to school and played with it during the music lesson.
Suddenly the teacher comes up and tells him to stop and put the DVD away. After he'd put it away, the teacher asks what's on it. As a joke one of my classmates said "It's PORN!!", so the teacher asked my friend if it really was, and he looked into the ground and said yes.. Meanwhile some other kid had taken the disk and handed it to the teacher.
My music teacher tried the DVD, out of curiousity...
Thats how we got to watch 10 seconds of hardcore anal porn in class...