I can top that one...
My school was located in a heavily Jewish neighborhood.
So, one fine morning, instead of the "Star Spangled Banner" for the flag-raising, the external PA plays a recording of the 1934 Nuremberg Rally--Deutschland Ueber Alles, followed by 100,000 Stormtroopers shouting Sieg Heil!
The principal looked up the hill overlooking the school (said hill known to one and all, including the Jewish community, as "Hanaukah Heights") and said, "Ah, s**t, I think we've just gone to war."