Serik
CAGiversary!
Direct2Drive is selling the awesome tower defense game Defense Grid: The Awakening for $9.99 this week.
Better yet, you can register the game with Steam using the CD key provided by Direct2Drive.
You can also download the demo through Steam is you want to try before buying.
Also: Gamersgate is selling Europa Universalis III + the first expansion for $10 this week, if you're interested in geeky grand strategy games
Let the digital distribution price wars continue.