Microsoft/Bungie press release:
“7/7” has long been heralded as “Bungie Day” by the Bungie fan community. This tradition 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 – which happened to involve 7 Halo rings, “343” Guilty Spark, Master Chief is Spartan 117, etc..). For more information, check out the Halo wiki on the web, the number of references to seven in the Halo Universe is quite staggering. (http://halo.wikia.com/wiki/seven) In many ways, seven is the ‘official’ number of Bungie, if such a thing existed.

This year, 7/7 will bring a few special treats to fans of Bungie and Halo but some are only available for a limited time so you’ll need to act quickly…

Commemorative Gamer Pics – on 7/7, fans can download 7 exclusive gamerpics, for free, from Xbox LIVE Marketplace. These are only available for one day and then they’re gone forever.

In addition to the pics, you can also obtain a special Bungie Day dashboard theme to adorn your Xbox 360. This too is only going to be available for download on 7/7.

Cold Storage, an update of Halo: Combat Evolved multiplayer classic, Chill Out, will be available to download for free. The emptied Forerunner research facility serves as a grim reminder of how even the best laid plans can fail. Warmly crafted, dutifully beautified update of Halo: CE classic multiplayer map, Chill Out. Love, Bungie".

Once, the Cold Storage facility was 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.

Starting on 7/7, the Halo 3 Legendary Map Pack will be available to purchase a new low price of 600 points. If you’ve yet to experience this epic collection of multiplayer battlegrounds, the time has never been better.

4th of July Weekend kicks off a special “Fourth of July” playlist where players can earn double-XP competing in a variety of Halo 3 gametypes (7/3 – 7/7).

On 7/7, the “Icy Treats” playlist is released which consists of all Cold Storage games (the new Halo 3 map) and offers double-XP. (7/7 – 7/9) Members of the Bungie team will be playing throughout the weekend so you may encounter one of the Halo 3 developers on the battlefield.

On 7/10, a special “Fiesta Double-XP” weekend kicks off, with Fiesta gametypes (random weapons) offering some unpredictable antics. (7/10 – 7/14).