Or is it a protest for Half-Life 3? Whatever.
The point being, This weekend over 30,000 members of a Steam group will sit down and play Half-Life 2. Calling themselves "A Call for Communication", the group says "we have decided to gain Valve's attention by delivering a basic message: Your oldest and longest running fanbase would like better communication."
That "better communication" would come in the form of any communication as to the whereabouts of Half-Life 2: Episode 3, or as it's more commonly believed to be these days, simply Half-Life 3.
Will it work? Probably not. But hey, any excuse to play through Half-Life 2 again is a good excuse!
A Call for Communication [Steam]