Halo: Reach Multiplayer Beta
From Halopedia, the Halo wiki
The Halo: Reach Multiplayer Beta is a phase in the development of Halo: Reach, produced by Bungie Studios and organized by Microsoft. The Beta will be released to the public on May 3rd 2010[1], and will be used to test different aspects of Halo: Reach multiplayer with the public, judging what to change based on public demand. The Beta will contain several maps and gametypes never seen before, and will showcase the new gameplay features in Reach. Little else is known about the Beta other then it will be released via the Halo 3: ODST disc.