Bundle Stars is given away free steam copy's of Pid via Facebook.
https://www.facebook.com/BundleStars?sk=app_174961479209942&brandloc=DISABLE&app_data=dlt-1
given away a free copy of gta iv for steam.
http://www.steamgifts.com/giveaway/sytQy/
to to enter you must join the steam group http://www.cheapassgamer.com/forums/showthread.php?t=147902