Gaming in Zion

What's a Steam group without events? Boring, that's what. Unfortunately, I don't know what the hell to schedule.
The obvious answer would be a TF2 night, but I'm not aware of a server we could use for that. Plus I'm not sure enough people would show up for a balanced game.
The other option is to choose a different game where a server isn't necessarily required. Something like Killing Floor where the game can be hosted by someone at their computer. Other than that, however, I'm not entirely sure which games support that particular feature.
So, what say you? Suggestions? Have a server can use? Is anyone even reading this?