Aaah. Chemistry in highschool. I had the luck to have one of the best teachers in the school. He was funny as all hell. In the beginning of the school year my assigned seat was in the front row, and at the beginning of class he sat up on the lab table in the front of the room almost directly in front of me. He was talking about something...don't really remember what, when out of the blue his leg from his knee down fell clean off. It hit the floor rather noisily, and he just looked down at it and said "Well...that wasn't supposed to happen." He then proceeded to put it back on. This was before I knew he had a prosthetic.
Later in the year he gave us a lesson on "How to check if your fly is open". Very...very amusing. He also had a set of GI Joes that he did horrible experiments on in class as well. One of them went into corrosive acid...another was set above a bunsen burner...another he tied to a rocket...