Another wheeze was to remove the plug on the u-bend of someone's wash basin. One victim was seen emptying the water after placing a gash bin underneath to catch the spillage. "Ha, ha. You'll have to get up earlier in the morning to catch me out that way," he boasted before emptying the contents of his gash bin back into the sink...
Then there was the occasion we had some Royal Engineers as guests, completely forgetting they wore spurs as we stood on the tables (one of which had come from the battleship on which the Japanese signed the surrender of Singapore) to perform the traditional after-dinner singing. The damage was costly.
When I asked one of the Sappers afterwards why they wore spurs, he said it went back to the Napoleonic wars. When an RE woke up next to some warm body in a barn where he had been billeted, he would gently rake it with his spurs. If it complained, he knew it wasn't his horse.
The less said about using the dumb waiter to mount a raid on the galley at 0500, the better.