Get a tub of plastic soldiers. Set up a war zone with dirt from your vege patch and a few bits of leaves, lichen and sticks etc. Choose the unlucky man to get hit and stand him in front of the guy with the rifle. Add a few coloured sprinkles, stick them on to your soldiers with a bit of spit (hey these guys are at war, they can handle a bit of spit). Get down and low with the camera. Shoot at f16 to get some depth. Bit of tweaking in photoshop with hue/saturation to give it that old time feel. Then spend hours with the spatter filter making those sprinkles look like runny paint. Wacko, you have yourself a fake paint ball war. Throw away the sprinkles.