No trolling, something might be happening.
Half-Life 2 is getting an update on Steam right now. Looks like the same update that gave us the potato sack stuff.
Also the official steam support page posted about it, then posted some Korean text that translates roughly to "Prepare for unforseen consequences"
And then a NEOGaf poster posted a leaked screen of next month's Game Informer magazine that is hinting at something from Valve.
It might be happening.