Treyarch has confirmed on its official Twitter account that a double XP weekend for Black Ops is now live for Xbox 360 and PS3. The developer also confirmed that 24\/7 Nuketown returns as well. On Twitter, Treyarch said, "You heard the man. Double XP is now live for 360 and PS3. Nuketown 24\/7 returns. Enjoy the weekend".ENJOY GUYS..