I made a tic-tac-toe with two different cupcakes using Paintshop and printed them on plain printer cardstock. The game says "Scratch off 3, if you get a tic-tac-toe you win!" Obviously I didn't win and kept scratching my test run. You can paint on the clear shelf liner and cut it out for a cleaner scratch area but these were a first try and they are for kids 6-8. I don't think they are going to care if my paint lines aren't straight. lol!
If you want to give this a try head over to ArtMind and she will show you how. : ) What games do your kids enjoy at birthday parties? For my daughter's party the kids are all going to decorate their own cupcakes. Any other game suggestions?