EA is giving away Mass Effect 2 as part of their "On the house" program. Mass Effect 2 is probably the best game of the series and a game that our own Jeremy Duff rated as near perfect. All you need to get the game is have a PC with Origin, EA's version of Steam.
I know a lot of people are loathe to install Origin but getting one of the best RPG's for free (along with all of it's DLC) is hard to deal to pass up and it's not like you can't uninstall it after wrapping up the game. All you have to to is click this link, sign up for an account, and install some software.