Our 10-year-old and his comrades love paintball and Army Men (plastic soldier) computer games. We wanted to do a paintball party, but considered real paintball to be too costly and potentially dangerous for this age. Instead, we put our "men" through maneuvers and then turned them loose with "splat" guns we found at Wal-Mart.(These use tinted goo and included safety goggles). In warm weather, water guns with a bit of food coloring would work, too. (Goggles still recommended).  Our computer-printed invitations used jargon like "Operation Birthday" and "fourteen hundred hours" and instructed "recruits" to wear "fatigues" (old clothes) and bring a "shaving kit" and sleeping bag. We also printed out signs for "Camp (your last name)," "Barracks," "Mess Tent," "Arsenal," etc.  Soldiers were issued dog tags and army caps purchased from an army surplus. We printed names (stencil typestyle) on clear mailing labels on the computer for the dog tags. (Permanent marker would also work). Our "sergeant" wore a camo field hat and a whistle.  First exercise: We borrowed 8 used tires from a tire store and staggered them for maneuvers. Second exercise: We filled green water balloons for a mine field in a mulched bed. One soldier was blind-folded and spun around in middle, then tried to exit without getting wet. Third exercise: parachute drop.  We used a zip line hung between trees and marked the drop with an X with chalk. Fourth exercise: tug of war.  We then led soldiers to storage closet in basement with "Arsenal" sign and armed them with "splat" guns. A cardboard practice target was rigged on the zip line to be pulled by "Sarge" and safety rules were issued w/ warning that even an accidental infraction would result in five minutes OUT of action. Lots of big trees, one big cardboard "fort" painted in camo and a treehouse were utilized by teams for evading hits.  Our birthday cake was decorated w/ micro army soldiers on a shaped cake with a chocolate pudding "quicksand hazard" inlet and "cookie-crumb" sandy shoreline. (The cake cut-away was placed atop remaining sheet prior to frosting to create a bluff and bits of crumbled cookie were used for rocks). One soldier was heard to comment that it was a really cool cake!