When I was a kid my brother and I used to fight wars with those little plastic army men and the plastic cowboys and Indians. But it was us against them.
It starts with a blanket that you toss onto the floor on one side of the room so that it makes a mountain-like pile:
Then you get your supply of plastic figures:
Next place the figures all over the blanket mountain.
Grab your supply of weapons:
Finally, from the other side of the room you shoot the rubber bands with your fingers at the mountain of "opponents". If you manage to knock one down he is dead.
The war ends when you run out of rubber bands. If all the little guys have been knocked over you win. If not, they win. And no fair having a monster supply of rubber bands so you will always win.
I will bet we conducted several wars even up into our teens.
I would love to do it again.