Microsoft plans to release exclusive Halo 3 content free to Xbox Live Gold members this week, according to a post today on the Gamerscore blog, an Xbox 360 and Xbox Live site run by Microsoft employees.
Gold members who click on the "Unite to Fight" ad on Xbox Live starting at midnight tonight will be able to download four exclusive Halo 3 items: a Halo 3 Dashboard theme, a Halo 3 Gamerpic, and two documentaries about the game.
The theme and picture pack will be available for download at midnight tonight. On Thursday, the "Inside Bungie: Halo 3 - The Story" video, which includes interviews with the Bungie team, will be available. On Friday, Microsoft will release the "Inside Bungie: Halo 3 - New Features" video in which Bungie team members discuss (surprise!) the game's new features.
If you have any time left, you might be able to actually play the game, which launches at midnight tonight.