Starting yesterday, the sale offers various games and packages up to 80% off and will run until January 2 in the new year.
The publisher packages in particular (THQ, Ubisoft, Sega, etc.) offer hundreds of dollars of savings for packages of multiple games, and these discounts will run for the duration of the sale.
Other individual titles are on sale daily, and will only be specially discounted for 24 hours.
So far I've picked up the original Mafia game for five bucks, The Burnout Ultimate box also for five dollars and Battlefield Bad Company 2 for about 14.
Bring on the Call of Duty series, Valve!
It's going to be a very merry holiday season for PC gamers this Christmas.