L.B.
Well one thing I did for my daughter for my son's games was to get her a Cheerleading outfit. Gymboree makes some really cute ones and there are a ton on ebay right now with Halloween. She really had fun cheering the guys on.
Another thing take a blanket and some dolls (either big ones or Barbie) that she can change out the clothes etc. ONLY let her play with them on game days...otherwise the toy won't hold her attention for very long. Do that with ANY toy you use for game day...leave it in the car and it only comes out at game time.