Starcraft II Public Test?
I have just realized there is a new menu item called "Starcraft II Public Test" which I think has been installed with one of the latest updates.
What is this? I'm not very comfortable with launching executables whose function I don't know.
Solution 1:
It launches a beta of the upcoming release of patch 1.2
Info: http://us.battle.net/sc2/en/blog/1334972