Battlefield 3's next DLC (and possibly final DLC? It's at least the last announced one I am aware of - Oh, no, there's also End Game, which has motorcycles, apparently) will arrive just in time for Christmas. The new maps, set in an earthquake-ruined middle-eastern city, look pretty fancy, and they provide a playground for new weapons and a host of modified vehicles. All this underwrites a new game mode. DICE explain that Aftermath "sees the debut of Scavenger mode – an objective based conquest where players must brave the environment armed with only one sidearm, as they try to find more powerful weapons in an attempt to survive with their squad."
Big fancy Aftermath trailer below, and there's a bunch more information here.