Originally based on Earthsiege and Cyberstorm, Starsiege is a mecha based warfare computer game created by Dynamix. It later expanded (mutated?) into Starsiege: Tribes, one of the earliest "massively multiplayer" first-person shooter games, and the other sequels in the Tribes series.
An community-based project to create a sequel to the game, Starsiege 2845 (http://www.starsiege2845.com), was officially sanctioned by Vivendi Universal to be released as a total modification for Tribes: Vengeance.