In gridiron football, untimed play occurs in the following situations: * Extra points following touchdowns are attempted without the clock ticking (except in arena football, which uses a continuous running clock) * If the clock expires while a play is in progress, the play continues untimed until the ball is dead * If, at the end of a quarter or a half, a defensive foul occurs, the offense is entitled to an untimed down * Specifically in Canadian football, if the clock expires while the ball is dead, play continues with one untimed down. (This is in contrast to American football, where if the ball is dead and time expires, the half or game immediately ends.)