Great Gaming Easter Eggs

Gamespot is running a piece detailing some of the most well known Easter Eggs in gaming history. The list starts with the first egg in a game, the Warren Robinett room in Adventure. From the article: "In the depths of the black castle in Games 2 and 3, which required special tools, direction, and a certain amount of know-how, players could maneuver to a room by the catacombs that had a single-pixel gray dot, the same color as the game's background. The dot would allow players access through a wall to a superfluous area with the text "Created by Warren Robinett" running down the middle. Robinett was partially motivated by the fact that, at the time, designers weren't given credit for their games."