Team Fortress 2 is getting a HUGE update tomorrow.
Mann Vs Machine
The idea of this Mann vs. Machine gamemode is that it's co-op. 6 people try and survive and defend a Mann Co factory. The enemies are robotic versions of all the 9 classes and some come in different sizes and have some unlockable weapons (e.g. Like the Huntsmen) So in a nut-shell, it's like L4D Survival only there's 6 of you and you have to defend a building.
Valve even made a fantastic video showing RED and BLU teaming up and destroying the Robots.
For any TF2 fan this is some exciting stuff and it sounds like a heap of fun.
So what do you guys think?
EDIT: Oh and not only that.
The Steam Community is having a huge update too.