Closest I've ever been was a few years ago, 9-12 years of age, we were the "War Club". Here are the rules:
1. Nobody TALKS about War Club. Just kidding, but it would have been fucking awesome if that were the case.
2. One hit from any weapon will kill you, to respawn, you have to head back to a friendly fort.
3. There are four "forts" (pretty makeshift, but we were able to pretend they were at least WWII bunker quality.) Team 1 has the fort that's furthest away from Team 2's fort, and the other two are conquered and owned by whichever team has the most living members at. If all your forts are taken, you lose.
4. You are only allowed to use fake (toy) weapons that have been tested by the others and deemed "Real enough to know that you were hit, but not enough to really hurt."
5. Scopes are overpowered, if you're going to bring a far-shooting nerf gun, you have to aim it yourself.
6. If someone stealth-kills you, they have to whisper "Stealth kill" to you when they do it. You're not allowed to do a dramatic death scream when you're being stealth-killed. Obviously, you can't stealth-kill very well using ranged weapons, which supposedly represented the loudness of real guns, unless the person you shot was kind enough to make quiet choking noises instead of screaming in fake agony.
I had some good times, lots of war stories and fake PTSD.