At first I wanted to say 2012. However personally it was 2011. In 2012 I had a terrible migraine during the OU game. Also, after WVU I went into "don't mess this up" mode.
Then I went back and looked at the 2011 schedule. The @Miami game, the Baylor comeback, beating Mizzou on their way out, winning at Lubbock starting off with the pick-6, 4 OT over A&M, winning in Austin, & winning a fun game against ISU in the rain (the diving pick). Those were 7 very fun games, plus I watched us destroy KU in Vegas. I also went to the the OSU game, and even though we lost, the game was fun.
Overall, in season, 2011 was the most fun for me.