High school was a bushel full of those for me.
My most embarrassing moment in school happened in grade 11. It was a late, late night for me the previous night. I had just sat down in class for first period. I looked up and saw that we had an on-call teacher for the class that day. So, thinking we wouldn't have to worry about handing in the homework assignment for the day, just sat back while everyone else did (We had a rule in this class; if the regular teacher wasn't there and you weren't done an assignment, you were lucky because you had a day of grace to finish the homework). The teacher watched as the last person handed in their assignment and went to sit down and then looked down at a piece of paper, then looked at me quizzically. She said to me "I'm sorry, what's your name?" I told her my name and she looked down at the class list (Which was that piece of paper) and then to me again. She said "I don't see your name on the class list." I asked her why it wasn't, and she said "Well, that's probably because your in Mrs. M's class this morning usually, not this one." Everyone in that class laughed at me; I had sat down in the WRONG CLASS
.
Anyways, from there I went to my regular class which was next door. Mrs. M asked me why I was late (Of course she was here so I handed her my assignment). When I told her this story we had a good laugh about it and excused me from being late.
As embarrassing as it was, it was actually pretty funny now that I think about it.