According to some sources *cough* Reddit *cough* the popular first person puzzle shooter Portal is available to install for free. This isn't the first time that this offer has been given, but it still remains to be a great one.
Simply put, Portal is one of the funniest puzzle solving games out there! Although it first came out a while ago as a surprise inclusion in Valve's Orange Box set, gamer of all ages rejoiced at the dark humor and creative design of the short game. Portal is a sweet 3 hour ride filled with sarcastic dialogue and interesting plot, as you find yourself trapped in a science laboratory and being forced to solve complex puzzles using a portal creating device. As you progress into the game prepare yourself to become further immersed in its brilliant plot, as each testing chamber brings new information and secrets about the history of Aperture Science and the sinister A.I. that now runs it. Trust me, its a game not to be missed.
So, if you have played it already, give Portal a shot. You might find yourself to be pleasantly surprised and fall in love with it as I have.
Install the game here: (requires a gaming application/client called Steam, which is used to distribute many computer games digitally. Also free to download.)