Sid Meier's history-based, empire-building games don't catalyze the maddening must-replay-NOW angst of Tetris, nor do they have the immersiveness of MMORPGS. No, the addictiveness of these destroy-ancient-civilizations video games is more insidious — it might be time for bed, but you promise yourself you'll just find the perfect place to found your second city, or quickly give Montezuma a much-deserved smackdown. And then you should probably find yourself a good source of copper, and decide whether to pre-emptively attack Bismarck, and... and then the sun is coming up and you're hunched over your computer, propping yourself up with an elbow as you repeat to yourself, "Just. . .one. . .more. . .turn."