We bought a football party pack of decorations (thanks to the fact that it's SuperBowl time)
We bought frozen pizzas and made them into football pizzas
We bought football cupcake papers and squeeze icing and let the kids each decorate their own football cupcakes
We made facepaint and painted the kids' faces with numbers of their favorite players or goalposts, etc.
They played blindfolded punter using a balloon as a football, and made an obstacle course they had to run while hanging onto the football. They had a little football toy they tried to get kick a ball through the goal posts and everyone went home with a balloon. The experienced football fans in our crowd stayed and showed us how to use our new football game on the Wii.