This weekend (9-11 December) will be Free for Gold. You can play your games with other guys, check Facebook, Youtube, Video Kinect, or just enjoy to just-relased demos. All thanks to a-bit-late update which was meant to come at the beginning of November, and it was relased today.
More informations:
http://www.xbox.com/en-GB/free-live-weekend?uid=126002278&tid=10461