For our school's homecoming poster, my class made football helmets out of paper plates. They were super simple to make and so much fun!
We got the idea from here and added speech bubbles. They looked really cute all together.
A few tips if you make them too: If your kids are young, cut out the face guard for them - it's kinda hard. We drew the face first with markers then painted the helmets. After drying, you can write your team name on the helmet. Stapling the face masks on was much easier than taping.