Steam's Midweek Madness sale is live, and the distribution service has slashed 50% off the entire Quake collection, including Quake, Quake II, Quake II Mission Pack: Ground Zero, Quake II Mission Pack: The Reckoning, Quake III Arena, Quake III: Team Arena, Quake Mission Pack 1: Scourge of Armagon, and Quake Mission Pack 2: Dissolution of Eternity.
All of the mentioned titles are $2.49, $4.99, or $9.99 each, or $14.99 for the whole kit and caboodle. Between the package discount and sale, you save $24.93. These prices should be available through Thursday afternoon.
It's also worth noting that the recently launched sci-fi action-RPG Mass Effect 2 is on sale via Amazon. For today only the game is $39.49 (34% off) for the Xbox 360, while the PC version is $29.49 (41% off), and Mass Effect 2 Collector's Edition for PC is $37.99 (37% off).