Halo 3 is free, at least if you're an Xbox Live Gold member.
From October 16 until October 31, Xbox Live Gold subscribers can download the game for free as part of Microsoft's "Games for Gold" program. The new program is an attempt to lure in more Xbox Live Gold subscriptions by offering two free games per month. New titles pop up on the 1st and 16th of each month.
A first-person shooter, Halo 3 is the third installment in the popular game series. Assuming the role of a supersoldier in the distant future, you battle a race of aliens in the middle of a galactic war.