I had to go with the Horns all-out failure against the Razorbacks. I think it just goes to show how over-rated Texas's recruiting has been over the last few years.
FSU's meltdown vs the Gamecocks would be my second choice. JSU looked bad in their 31-0 season-opening loss to UAB, but they came close to upsetting the Seminoles last year. They beat FIU by 9 last year and had an even more impressive win a few years ago vs Ole miss (49-48 if I remember correctly).