High School Football Halftime Show Circa 1950 (Vintage 8mm Home Movie Footage). American football is a sport played between two teams of eleven with the objective of scoring points by advancing the ball into the opposing team's end zone. It is known in the United States simply as football, and it may be referred to as gridiron informally or outside the United States and Canada. The ball can be advanced by running with it or throwing it to a teammate. Points can be scored by carrying the ball over the opponent's goal line, catching a pass thrown over that goal line, kicking the ball through the opponent's goal posts or tackling an opposing ball carrier in his own end zone. In the United States, the major forms are high school football, college football and professional football, which are played under slightly different rules.