
I remember well using Left 4 Dead as the defacto meeting place for the volunteer staff what at the time was a large well known website. You'd be surprised at how good you can get at if with the same team. If anybody is still playing it, try and play as two pairs with one pair advancing and then kneeling (so the people behind can shoot over their heads) and the second pair providing covering fire, we actually used to advance through the insane rushes without appreciably slowing down by doing this.
The community manager liaison between the volunteers and paid staff however had a few things to say about our meetings being done in this game. Apparently persuading the company IT department that it was absolutely necessary that he have a work a PC capable of playing Left4Dead, plus a copy of the game, a gaming headset with a mic and having the ports required allowed through the firewall during working hours led to bureaucratic warfare on an epic scale which only got worse when his boss wanted to join us to have occasional chats too.
Which to be fair as an IT Professional I do appreciate, since I can imagine my reaction to getting the same requests from my users...