The 2001 AFC divisional playoff game between the Oakland Raiders and New England Patriots will forever be known as the "Tuck Rule Game."
With 1:50 left in the game, on a snowy night in Foxborough, Massachusetts, QB Tom Brady and the Patriots' offense were driving in Oakland territory trailing by 3 points. Brady was blitzed by Raiders DB Charles Woodson, who hit Brady and knocked the ball loose. Even though Brady's arm was moving back toward his body with the ball, referees ruled it a fumble and reviewed the play.
That's when we learned about NFL Rule 3, Section 22, Article 2, Note 2: "When [an offensive] player is holding the ball to pass it forward, any intentional forward movement of his arm starts a forward pass, even if the player loses possession of the ball as he is attempting to tuck it back toward his body.