Mass Effect 2.
Yes, EA is giving away Mass Effect 2 for free through their On The House program. EA did not specified the duration of the giveaway, but usually the game is free for three (3) months. Register to EA, then download and install EA Origin client, from there you can get the Mass Effect 2 for free.
Dirt Showdown is also free for a very limited time (8 hours left as of the time of writing). You can get the code from Humble Bundle Store and use the code to download it using the Steam client. Hurry!!!