A huge series of anime and games that is based on an MMORPG called "The World." The .hack titles consist of, in order of the 'timeline'...
.hack//SIGN ...an anime
.hack//LIMINALITY ...an anime
.hack//INFECTION ...the first game in the series
.hack//MUTATION ...the second game
.hack//OUTBREAK ...the third game
.hack//QUARINTINE ...the final game
.hack//LEGEND OF THE TWILIGHT BRACELET ...an anime
The world of .hack could certainly be coming to us in another five years or so, when virtual reality is harnessed completely.