You can take advantage of the deals right now if you're an Xbox Live with Gold Member, but everyone else will have to wait until November 23.
Even better, you can now pick up some of the games on sale in Microsoft's store as gifts. Just use the site as you normally would, but click "Buy As Gift" when you're checking out. You'll then be prompted to enter the intended recipient's email address, and then they'll get a code. Here's a more in-depth how-to if you need it.
Like a console Steam sale
The discounts and the amount of games for sale are frankly astounding, as some of the cuts go as deep as 64%. Many of the juggernaut hits of the year can be found in the sale, including Assassin's Creed Origins for $42 rather than the usual $60, and Destiny 2 for $39, compared to the retail price of $60.
Essentially, if a game you want has a listing on the store, there's a good chance you'll find a discount for it.
On top of all this, earlier this week Microsoft announced that it intends to slash the price of the Xbox One S down to just $189 for Black Friday, which makes this a perfect time to rack up some games if you plan on taking advantage of the offer.