Also very common practice in the Russian army :)
The wooden spoon prank is one of the great group pranks, especially if you have a big group of spectators that won't ruin it right away. What you do is get three wooden cooking spoons and an accomplice. Your accomplice will challenge your victim to a game where they take turn seeing who can hit each other's head the hardest with a wooden spoon held in the mouth. The victim goes first, landing a weak hit on your accomplices head. What the victim doesn't know is that you have a spoon too, and are standing behind them. When it's your accomplices turn, whap the victim on the head hard with your spoon and pull back quickly so they think that your accomplice hit them that hard with his mouth. Repeat until the victim is confused and embarrassed enough to reveal the secret to.