Running out the clock
In American football, each quarter of a game is measured with a 15-minute game clock, or 12-minute clock in many high school football codes and the German Football League. A team in possession of the lead and the ball will attempt to use up as much of the game clock as possible in order to bring the game to an end more quickly, thus denying the opposition another chance on offense.
International rules football
An international rules match lasts for 72 minutes (divided into four quarters of 18 minutes each). Inter-county Gaelic football matches go on for 70 minutes, divided into two halves, and Australian rules matches consist of four 20 minute quarters of game time, although with the addition of stoppage time, most quarters actually last between 25 and 30 minutes.