8. Call of Duty World At War: Nazi Zombies
Possibly the greatest cure for boredom ever invented, Nazi Zombies is an unlockable bonus campaign on Call of Duty: World At War that arguably became more popular than the game it was included with. Your one and only objective is to hold down a bunker and survive wave after wave of Nazi Zombies for as long as possible using a combination of luck, skill, and tactics - from repairing barricades and distributing bonuses to regrouping and buying weapons. Never before has a game kept you on your toes for so long and been so infuriating and fun.