We did an army party for my son's 8th birthday.  We set up a tent in the backyard, with a cardboard sign painted with HQ. As the boys arrived, they but on camo face paint (found at a sporting goods store), also got an army tatoo and dog tags(oriental trading), we made camo vests and issued helmets.  We had a hand gernade toss (we made bean bags out of camo fabric & filled with rice and set up a board between two cement blocks and stood up  different size pop bottles).  We did a land mine walk, set out a bunch of water ballons and blindfolded each solider, they tried to make it through without breaking any balloons, we also set off some bomb bags as they walked through.  We had a cookout and ate outside, I made another sign that said Mess Tent. The boys played medic, one had the medic bag, which had a couple of rolls of toliet paper.  The other boys drew "injuries" (broken arm, head wound, eye wound, broken ankle, etc.) from a paper sack. We did a lot of "bang, bang" & "kaboom". The injured boys fell to the ground, the medic came running and without words, he had to figure out what body part to bandage. After everyone was bandaged, we checked the papers to see how the medic did.  We also played diffuse the gernade.  Everyone got three balloons which had a small present inside and they had to pop their balloons, just using their bodies.  We had birthday cake, which was a army battle field.  Chocolate cake & frosting, a sheet cake I cut a small area out and turned upside down to make a little hill, filled the hole with blue tinted pudding to make a lake.  I crushed some chocolate graham crackers and vanilla wafers for dirt and spread over the cake. We set up an army battle using the plastic army toys. We had camo plates, cups, napkins and tablecover (oriental trading). We had a obstacle course: walked along the plank (from the bean bag toss), over the pool (we set empty milk crates upside down in a small pool), under the "wire", rope my husband strung across the yard, run through the tires, through the tunnel (an empty fridge box we spray painted greeen & brown), swung across another kiddie pool, climbed up the play set, at the top they found their paratrooper and dropped over the end trying to hit the orange circle painted below. We filled camo water balloons (Joann Fabric) and issued everyone a water gun (with their name on with permanent marker). They were divided into two teams, we had red, white and blue ribbon with either stars or stripes, they wore the ribbon on their wrists.  The water fight began.  For goody bags we used camo fabric and sewed bags, and tied with a piece of rope. We got USA pencils & pins and bomb bags (oriental trading), they also took home the vests, helmets, paratrooper and squirt guns. We did put a note on invitations that recruits would get wet & dirty, so send a change of clothes.