Things that went wrong today, that were out of my control:
1. Neither of the overheads in the room had any transparency roll left. (I stole one from the next room... don't worry, I let the people in charge know.)
2. The fire alarm went off shortly after class started. (Someone didn't want to learn more about b-smooth functions?)
3. The overhead roll didn't want to stay on the holder. (Luckily putting it on the shelf below did the trick.)
Other than that, things went smoothly.