Tons of free games on there and they are easy to find.
Blacklight Retribution is a good FPS and won't cost you a penny for example.
World of Tanks is completely free but not available on Steam - Google it.
Most MMO's are either free to play or have an f2p element.
Planetside 2 will be free when it releases at the end of the year.
Probably not the answer you were looking for but really, there are some top titles out there that you can legitimately play for free without having to download dodgy warez cracks that could end up costing you dearly in the long run.
I think its pretty hard to download games for free these days with all the authentification and DRM, unless as said above you play world of tanks & other free games available through Steam. Gone are the days of easily downloading games from torrents!