For my son's 5th birthday, he had a GI Joe party.  We bought all the GI Joe paper products, including the invitations, which invited the kids to report for a secret mission. The invitations were addressed to "GI name of child." My son and my whole family (including Grandma and Grandpa) were dressed in military fatigues. I even had dog tags made for my son (military surplus store.)  Our basement was decorated with military posters, including the famous Uncle Sam "I Want You for U.S. Army" poster (military surplus store) and maps of a military base (dollar store.)  When each child arrived they were checked in and issued their  GI gear: a helmet (Oriental Trading), dog tags (Oriental Trading)with their names (I used clear laser labels), a camouflage canteen (dollar store) with fruit punch in it, a nametag "GI name" and their camouflage make up. The children had free play, which of course included mock battles and lots of play with GI Joes. We also had a magician dazzle the kids with his tricks and of course a real rabbit. There was a full dinner for children and parents (since the party commenced at 5 p.m.). The cake had a copy of the GI Joe invitation created on it in frosting. The candles were placed in Toy Story green soldier lollypop holders (I removed the lollypops). The cake was served on pie tins (which looked like military tins). We had a tank piñata (Birthday Express) filled with toys and gifts, which included parachute soldiers.  They were given GI Joe goodie bags to fill with the piñata loot. At the end of the party, the children were given secret attaché cases (Birthday Express) filled with small green soldiers, Toy Story green soldier lollypop and holder, a compass, small military vehicles, soldier with parachute, stickers, camouflage pencil, binoculars and candy. We took pictures of the kids in their gear during the party, which we included in the Thank-you cards.  The kids had a blast and almost a year later are still playing with their gear.