The tradition of Bungie Day was born in part due to the significance the number 7 has played in all of Bungie’s games over the years, including the “Halo” series (7 Halo rings, Master Chief is Spartan 117, etc.), and each year the developer makes a point to use this date to treat fans to something special – usually new content, a free download or other surprise.

This year marks the best “Bungie Day” yet, as eight million plus “Halo 3” players can now download Cold Storage, a free new multiplayer map inspired by the original map Chill Out found in “Halo: Combat Evolved.” The Cold Storage facility was once a vibrant, active research center on Installation 05. An accidental contamination resulted in an unforeseen outbreak, which compromised the Forerunner center. Now, emptied and silent, watched only by a local caretaker, the abandoned structure serves as a reminder of how something as powerful as science is ultimately beholden to nature.

In addition to the new map, players will be able to download 7 exclusive new gamerpics and a Bungie Day dashboard theme for free on Xbox LIVE Marketplace. Fans will need to be sure they download these on 7/7, because they will be available for one day only.