The ones for whom it was not fun were the ones in most need of the game.

It's natural to be afraid of pain. It's your body's signal for damage. But pain in that kind of controlled environment, where you know you are fundamentally safe, and no damage will occur, gives you a chance to get over your fear of pain, which in most cases is much more painful than the pain itself.

There are few things that a child will face that is more painful than the fear of pain. I think it's healthy for a child to be gently led out of that fear. When I was young, I was too afraid, and wish that someone had helped me to get past it.

Glad to know it wasn't just my own summer camp which was that deranged.

Far from it. I suspect it's a fairly universal game, either to signal "I am tough", or practice for handling pain or fear.

The version of this game popular in my country involves taking turns kicking a soccer ball at each other from a given distance, usually while the target is facing a wall. Whoever kicks the ball is up next, even if they miss. I assume it is a positive sum game, because kids would play this game of their own volition, though that could be because they don't want to refuse when invited. It was a rather uncommon game, relative to proper games.

I've also seen a game called "mercy" where the fingers of both parties are interlaced and bent backwards until someone gives up, the game called "chicken" involving driving cars at each other (which I've heard a lot about but never seen played), the crushing handshake, truth or dare. However, the most intriguing one is the drinking contest.