Valve has released news about a post-holiday sale on many of their games ranging from 25% to 75% regular prices.
Cinema Blend writes: "Titles such as Bioshock and Portal are actually up for grabs at 75% off the regular price. Yikes, that's a good deal. Particular items from Ubisoft, THQ, and 2K Games are also all available at 25% off the retail prices. Honestly, sounds like a good deal to me. "