I don't know if anyone has noticed yet but there's this sort of special event going on for steam users called the "Potatoe Sack" in which if people play a select 13 indie games enough times, Valve will release Portal 2 for PC and Mac early on April 19th, which is tommorrow. Out of the 13 indie games, 6 have been completed.
Heres the link that explains everything:
http://www.aperturescience.com/glados@home/
There isn't much time left! Come on guys, I know everyone here wants Portal 2 early