The Purge: Anarchy

It's 'Purge' time again: the one government-sanctioned night every year in which lawlessness--including murder--is permitted. With residents desperately trying to avoid the bloodthirsty hordes, one heavily armed man on a mission of his own becomes the unlikely guardian angel of four innocents. A 'satisfyingly creepy, blunt, down-and-dirty thriller' (New York Times).