Today is definitely your lucky day (go ahead, grab a fortune cookie). If Command & Conquer Gold for free wasn't enough to satisfy you, another game company, Ubi, has given away 4 of its games. These games include Far Cry, Tom Clancy's Ghost Recon, Prince of Persia: The Sands of Time and Rayman Raving Rabbids.
Before you start wondering if the world's gone totally mad, note that technically they are not really "free". They are free of charge in terms of price, however they are not free of advertising. Yup, these games are released with adware in them. And there's a big problem for international users.
You will need an Ubi.com account and you must live in the U.S. to play the game.
If you qualify and don't care about the adware, you can grab them at these places.
Far Cry (2.68GB)
Tom Clancy's Ghost Recon (542MB)
Prince of Persia: The Sands of Time (1.13GB)
Rayman Raving Rabbids (1.25GB)