What would you do under these circumstances : Need some help making a decision?

Why can't you tell him how you feel? Just because he got the tickets when you clearly told him that you would check your schedule before you gave him your decision, means that he is not respecting your time. You need to lay clear ground rules about your friendship and this seems to be a good opportunity to let him know that by your action. If you truly will not enjoy the game for 12 hours, tell him that and do not go. Since the tickets are free, he can find someone to go with him. It seems to me that he just wants some company at the game, and that does not have to be you since your time is valuable.