Steam News has word a new patch is now automatically available for Left 4 Dead 2. The new version has localization updates and fixes and adds this week's mutation, which is called Gib Fest. The Left 4 Dead Blog has further details on the new mutation: "Blast the infected to shreds with M60s. Swords can slice up some fun. Chainsaws can tear apart the infected. But you need to get close for both and well… chainsaws are really loud! Time to go with the ultimate gun, you and three friends armed with M60s and unlimited ammo. This is going to get messy." There's also an article on the Left 4 Dead Blog with a breakdown of all this mutation madness.