2015 Illinois, 14-13. We led 13-0 going into the 4th quarter. Late in the 4th quarter we still had a six point lead. Then we threw an incomplete pass on 3rd down, stopping the clock with about a minute left. The punt gave Illinois the ball on their 28 yard line with 51 seconds on the clock. They drove down the field through our Swiss cheese defense, and threw a 22 yard TD pass with 10 seconds on the clock for the win.
Aside from incompetence on the field, this was the first game I took my young son to. It rained. We lost. Worst. Game. Ever.