1951: NIMROD
Category: Laboratory
The first computer built specifically to play a game. The size of a couple of refrigerators, its purpose was to convince visitors to a science exhibition of the advantages of the new digital computers. It was built by Ferranti, and based on their Mark I computer model. All it did was play the game of NIM against a human player. Wikipedia has nice articles on the rules of the game, as well as NIMROD, with a very nice sketch of it.
