I think it is in Q3 when Tearrius George tackled Calvillo around 1-yard line. Since it was a horse-collar foul he got flagged immediately. George, oblivious to what was happening, dancing around and celebrating his "big tackle" while the referee and AC were discussing the penalty.
A few seconds later he realized what happened. His expression... priceless.
I thought that was really funny too. The way he was celebrating that tackle made it all the more entertaining when he found out the flag was against him for that very tackle. The commentators made it even funnier by pointing out just how blatant a penalty that was