Gamecloud has a piece looking at some worthy games that never made it to market for one reason or another. The one that hurts the most for me is Microsoft's canceled, but intriguing, Norse MMOG Mythica. From the article: "Date of Cancellation: February 2004. Microsoft Games Studios decided to get into the MMORG genre with this fantasy themed game that was announced with much fanfare in April 2003. This game, with a Norse mythology theme, was going to have more of a single player experience than most MMO games. However, less than a year later Microsoft decided to shut down development of Mythica with the team all laid off as well."