Flash sales today include Batman: Arkham City GOTY ($7.50), Natural Selection 2 ($10), Fable 3 ($25) and War of the Roses ($15). The Indie Super Mega Pack includes 30 games each discounted up to 75 percent off, bundled for $70. There are a range of publisher packs as well, from Ubisoft, Valve, THQ, 2K Games, Bethesda, Sega and Square Enix.
Check out all the day's deals on the Steam Store. The Holiday Sale runs through January 5.