Give a man a fish and feed him for a day....Teach him to use the internet and he won't bother you for weeks!
One of the most influential video games ever would have to be Pac Man. It's design seems charmingly simple now, but it's broad-based appeal remains even today as virtually every gaming platform offers a version of the game. An almost overwhelming amount of interesting trivia can be found in the Wikipedia entry on the game and its' history. I didn't know that the original title was Pakku-Man, which was changed to Puck Man, and then to Pac Man, out of fears that arcade vandalism would quickly turn Puck Man into something less wholesome. A few video links reflecting the influence our little yellow friend has had: