Sid Meier's Civilization
I can't remember how often I played this game. Civilization is one of the most memorable games of my childhood. Trying out new civilizations, world configurations and leaders, trying to beat the computer, sometimes playing peaceful, other times playing aggressive: It's a fantastic game and a single game means hours of fun. It's still one of the best games to replay. Originally, I never owned Civ so I had a less-than-legal copy on my computer. When I saw this re-release on CDROM in a store, I instantly bought it.