The Passing Tomorrow, And "Mutations"?

Free Left 4 Dead 2 DLC The Passing is out tomorrow. It's got lashings of content, including new infected and new weapons. But here's the really interesting bit:

The Passing also introduces a series of weekly game mode events dubbed "Mutations." These week-long runs of new gameplay modes range from "Realism Versus" mode to "Chainsaw Massacre," which gives all players chainsaws with an unlimited supply of gasoline. There are over 20 Mutations planned, each playable on all L4D2 Campaigns. Mutations are exclusively available to owners of "The Passing" DLC.

It'll be interesting to see how those things play out. Warming up my cricket bat tonight, in anticipation.