American football
In the NFL, college football, and high school football in Texas (whose rules are based on the NCAA set), if the defense takes possession of the ball during an extra point (via fumble, interception, or blocked kick) and returns the ball into the opponent's end zone, the defensive team receives 2 points. (In high school football outside of Texas, if the defense takes possession during an extra point, the play is dead at that moment and the conversion is ruled "no good".)