As we reported last month, Halo 3 is October's second free download for Games with Gold, following on from Might and Magic: Clash of Heroes HD. Xbox Live gold members can download it right now from the Xbox Live Marketplace, after which time the game is yours to keep forever.
There's something quite poetic about having Master Chief's Xbox 360 debut being among the last free titles on the platform before the Xbox One launches next month (next month! Can you believe it?). Halo 3 was one of the titles promised by Microsoft when the Games with Gold program was launched all the way back at E3 in June.
Any guesses/requests as to what the next free games might be? The program is set to run until the end of the year at least, but at our Xbox One community event recently, Ed spoke to Xbox Live product manager Pav Bhardwaj, who hinted that it could "evolve" into something else into 2014.
Update - Microsoft has also discounted Halo 3's Mythic II Map Pack. £3.37 gets you three maps - Heretic, Citadel and Longshore.