The Debian/Ubuntu Games Team provides packaging and support of games in Debian and Ubuntu archives. From RPGs, FPS's and RTS's to flight sims, board games and art games, we work collaboratively to share problems, bugfix, package and promote FOSS games in all genres and we seek new members to assist us in our work. We have roles for all technical levels. From producing screenshots and documentation, building packages of existing games, tracking down new and interesting games for inclusion to helping with licensing and source materials of games and art. If you have a passion for GNU/Linux, love gaming and want to help make the base distro of Ubuntu, Mint and many others even better then please contact us on IRC #debian-games on irc.oftc.net or via our mailing list at email@example.com .
As the upsteam source of many popular distributions (Ubuntu, Mint etc.) this is quite an influential team when it comes to open-source games
Although it seems other, less distribution and platform dependent, means of managing your games (e.g. Desurium and the like) seem to have partially replaced the Linux repositories, especially since those tend to be really out of date, thus not that useful for dynamic and regularly updated multiplayer games.