Valve recently announced The L4D Survival Pack, which will include a new game mode and two new campaigns for Versus mode. Both PC and Xbox 360 players will have access to the new content. The new mode, called Survival Mode remains enigmatic, but what is certain is that the Source Software Development Kit (SDK) will become available this spring. That means new maps, new mods, new brutality!
Until then, here's a list a few fun L4D Mods that might help hold you over.