Have you been hiding under a rock for several years? Perhaps I can suggest you play the fantastic PC/Mac Puzzler Portal, because it’s free now. Atleast for the next 4 days you can pick up Portal on Steam for absolutely free. In case you don’t have Steam you can get it here and not only are you on your way to an amazing puzzler, but you also finally have the best way to buy PC games.
Portal 2 is also available for 30 dollars and just as fantastic and even funnier than the first game so if you like what you see with Portal 1 then you need to pick it up.