From Friday, May 23rd (10am/PST) to Tuesday, May 27th (10am/PST), players on Xbox One and Xbox 360 will be able to download the demo and try out Call of Duty: Ghosts Multiplayer at no cost. Included are three Multiplayer maps – Strikezone, Warhawk, and Prison Break; three Multiplayer modes – Search & Rescue, Domination, and Team Deathmatch; as well as the original Extinction game mode – Point of Contact.
This is, what, at least the second or third time they've given a free weekend for this game on the Xbox platform alone. There were other free weekends for other platforms tossed in as well. So, I can only assume that the string of free weekends means that the game is doing quite well on all platforms.
If you really need any additional info, you can get it at the Call of Duty site.