Field Day Party    My husband and I had an old fashioned Field Day party for our 9 year old twin sons.  They each invited all of the kids in their class. We used sport theme invitations. We reserved the playing field behind their school with the town recreation department (this didn't cost anything). Everyone met at the field on the day of the party. We then held typical field day games: broad jump, relay race, football distance throw, sack race, etc.  First place winners got plastic trophy cups purchased from a party store. Everyone else got medals on red, white and blue ribbons. The party favors were old fashioned kids games like jacks, marbles, paddle balls, etc. We served a sports theme cake and had Gatorade to drink. This kept everyone entertained.  Our only problem was that we didn't make the party long enough. I would suggest a minimum of three hours. And keep the relay races really simple!  It was a good party for a large group of children who were old enough to cooperate and follow directions. And it didn't break the bank!