Star ArmyŽ is a forum community for roleplaying, worldbuilding, and collaborative writing, based in a shared, living space opera setting.
Since 2002 members have run hundreds of campaigns and written thousands of wiki articles that have become part of a rich setting bigger than what a shelf full of tabletop RPG sourcebooks could hold. It's a unique and original universe characterized by heavily armed starships, power armor, hardcore cyborgs, diverse aliens, and transhuman androids.
Things your characters do and ideas you contribute get built into the Star Army's history and lore. Join as a member of the Star Army of Yamatai or many other factional groups, or blaze your own trail as an independent adventurer or new faction.
5150: Star Army* is a military sci-fi tabletop wargame that shares our name (but is unrelated). It revolves around infantry squad combat, using miniatures. You can get it from the fine fellows over at Two Hour Wargames.