Before the day of the party, bake a sheet cake and decorate it to look like a football field. First, ice the entire cake with green icing. Next, fill a pastry bag with white icing and add lines to the cake to look like yard lines on the football field. Don't forget to add the numbers and the end zone!
You can also décorate the cake like a soccer field.
If you want to get extra creative, make goalposts by dipping pretzel sticks in melted chocolate and arranging them on parchment paper so that they are in the shape of a goalpost. Cool in fridge overnight, then assemble on your "end zones".