The first video game is an often debated topic. The idea of computer that could play games actually dates back to the inventor of the computer himself, Charles Babbage. While designing his never completed Analytical Engine in 1837, a machine he hoped would be able to carry out any mathematical function, he realised it would be capable of playing simple games such as tic-tac-toe and chess.
The first actual computer that played a game was called the Nimatron. It was developed and built by Edward U. Condon in 1940 to play the Chinese game of Nim. The game was displayed 'visually' by illuminating columns of lightbulbs. That same year it was demonstrated at the New York World's Fair where it was played by 50,000 people.
The first computer game to be displayed on an actual screen was called OXO. It was written for the EDSAC computer by Alexander S. Douglas in 1952 for his Ph.D thesis on human-computer interaction for the University of Cambridge.
Spacewar! developed by Steve Russell in 1962 is the first computer game developed for an already existing system; the PDP-1 computer. This also made it the first game to be distributed. The source code was made available to anyone who requested it.
Computer Space made in 1971 by Nutting Associates was the world's first commercially sold video game of any kind. The coin-operated video game was created by Nolan Bushnell and Ted Dabney, the later founders of Atari.
A year later in 1972 the Magnavox Odyssey, created by Ralph H. Baer, became the first commercially sold video game console.