Gameplay trailer showed by Bungie at MS E3 briefing on June 1st, 2009. Also announced by bungie was a Halo Prequel, called Halo: Reach, which ships Fall 2010.The Halo 3: ODST stand-alone expansion* will be released on September 22nd, 2009, and will include an invitation to the Halo: Reach Xbox Live Multi-player Beta. Nice way of pushing sales of ODST, lol.*Technically it isn’t an expansion, but you can compare ODST to Halo 3 as Crysis: Warhead was to Crysis.Bungie's ODST summery: "Much more than an expansion, Halo 3: ODST allows players to explore dangerous new ground, search the dark, abandoned streets of New Mombasa for clues, and fight back against the Covenant invasion from multiple perspectives. Dropping in as "the rookie," a new member of an elite squad of Orbital Drop Shock Troopers sent into New Mombasa on a classified recon mission, you'll be armed with specialized weaponry and upgraded technology, including silenced weapons and a VISR enhanced vision mode.Separated from your squad, you'll have to scour the city for clues in order to learn what happened to Buck, Dare, Dutch, Mickey, and Romeo. As you collect new clues, youll experience the story from their perspectives, fighting through the occupied city hours earlier."The game takes place between the events of Halo 2 & Halo 3.