Major Nelson posted the good news on his blog yesterday.

“If you haven’t had a chance to check out the latest entertainment experiences on Xbox, this weekend is a great chance to give it a try. From Thursday, Nov. 29 through Sunday, Dec. 2, we’re unlocking Xbox LIVE Gold in Argentina, Australia, Brazil, Canada, Chile, Colombia, Hong Kong, India, Japan, Republic of Korea, Mexico, New Zealand, Singapore, Taiwan and the United States.
All Xbox owners in these regions, regardless of their current subscription, will have access to online multiplayer gaming, (like Halo 4 Spartan Op) Internet Explorer, Video Kinect and our entire catalog of entertainment apps, during that time period.
Have fun“

Great news for all you Silver members that haven't had a chance to use the exclusive gold features and have been thinking about upgrading your Xbox accounts.