http://store.steampowered.com/ and direct link to the COD page on Steam - http://store.steampowered.com/app/10180/

Free all weekend!  I probably am not going to end up buying it though...they still want $60.  I'm not buying because it is out of my price range, but I am trying to save some money, plus there are a few other games I want to get first - Supreme Commander 2 or Command & Conquer 4.

And I haven't done a "Three Games I'm Playing" recently...will do that soon!!!