In my final year, the school actually had a fire (the weeek before I and my fellow 6th formers went on A2 studyleave).
The electronics in the boiler room caught fire and 'asploded. On the (then) hottest day of the year.
Last 2nd to last period, I had double free so was in art. Heard the alarm - during my 7 years there, we'd had so many drills (and accidental alarms - tennis racket hit alarm, minor explosions in chemistry, for a month the alarm went off every day because of a fault - Fire Brigade still had to come out, the day an inspector thought the fire alarm was the door-lock release...) - that everyone pretty much thought "oh goody, another drill"
Decided to leave my gear in art. Low and behold, it was a real fire.
Spent the rest of the afternoon in the yard waiting for the firefighters to put out the fire. To add a bit more excitement, our DofE instructor kept his highly explosive gas cannisters in the boiler room... For the rest of the week the building stank of burnt electronics and had no electricity.
The other thing...
The Royal Navy landed a Lynx helicopter in our yard/playground.
We knew that a former student was a high-ranker in the Royal Navy. We knew he was coming in to give us a careers talk on the Navy. We weren't told that he was a helicopter pilot, nor were we told that he would be landing his helicopter in the school grounds...