Eat a cougartail and a brownie at the stadium. This is a MUST! I'm salivating right now at the thought.
After the game go to the BYU Creamery. Excellent food at a great price. Down side is you will likely have to wait in line for a while.
If it's good weather a hike up to Timpanogos or a hike up to the Y are worth your time.