The one that seems kind of strange in hindsight was watching Stand and Deliver in math class. Not really useful in terms of the curriculum. I suppose it was just to get us excited about math. We didn't really care at the time, as long as we could watch a movie for two periods instead of actually doing math.
I recall watching this in social studies. The teacher was a rabid worshipper of the teacher in the movie.
Another thing that rocked was assembly day. I recall them having a mime perform in my high school once. They guy was a genius and even imitated a "condom" by the request of a student in the crowd. I don't think the teaching staff approved of it though. I also recall jugglers and a metal band performing. Of course every one of them had a message, "don't do drugs". Kind of reminded of the South Park episode where they had a goofball group of performers that were encouraging people not to smoke. Of course, all the kids did the opposite so they wouldn't be like the performers.
Side note, the metal band who did the concert in my high school performed at night. The teachers simply didn't understand moshing and suspended a few kids.