If you hadn't said 'gamer' in the title I'd have thought air conditioning, but since you did I voted Assassin's Creed.
... huh
only person who thinks alternating current first? Ok.
now ask MP
multiplayer, magic/mana ponts, metroid prime, mario party... max payne
or just member of parliament >_>
armor class, because even without playing much d&d, or even d&d video games, pretty much any acronym that was in everquest makes me think of it. specifically, that yellow shield icon for AC buffs.
If you hadn't said 'gamer' in the title I'd have thought air conditioning, but since you did I voted Assassin's Creed.