In celebration of Bungie day 7/7  there will be a free Halo 3 map available called Cold Storage.  This map is a remake of the original "Chill Out" map from Halo: Combat Evolved.  So if you want this map free, along with some gamer pics and a theme, check them out on Monday.  This content is free and available on Monday ONLY.  If you go looking for it on any day other than July 7th you'll be out of luck.