Due to the great sales number on their black Friday Xbox One bundles, Microsoft announced that the sales would be returning, beginning today. Lasting through December 26th, all of the Black Friday bundles will be on sale beginning at $299 at a $50 discount. The 1TB Xbox One bundles will also have the discount applied.
In addition to the bundle sales, on December 22nd, Microsoft's "countdown" sale would begin with discounts on over 200 digital games. The sale will last into the new year through January 7 and include digital games purchased on Xbox One, as well as specific retailers nationwide. These, of course, will vary depending on location, so you'll need to do some research if you plan to purchase at a store.