What is the most embarrassing thing that ever happened to you at school?

In middle school (grades 6-8) the boys and girls locker rooms were right next to each other (bad design) and there was only the tiniest of signage over the door saying which was which. Anyway it was changing time and we had to shower and get out of gym clothes into normal clothes. The door opens and in walks this 6th grade girl unaware which locker room she was in bumps into me and another classmates. She screams and stares "oh my God you guys are naked" and runs out.