The Internet archive has added a new attraction to their website. SPACEWAR!
Originally developed in 1962 at M.I.T., Spacewar! was run via papertape on the DEC PDP-1. There is now only one functional PDP-1 at the Computer History Museum in California. Read more about it’s restoration here.
As for playing the game now, check out the following over the Internet Archive. The controls are a bit different, and the game requires two players.