In this incredibly awesome Left 4 Dead PC mod, the polar opposite worlds of zombie infested gloom morph with the jovial and colorful Mushroom Kingdom of Super Mario 64.
Dubbed, “Mushroom Massacre,” this altered level makes me want the PC version of the horde-fest so so badly, or for Valve to release community-made levels on Xbox Live.
More at the Mushroom Massacre page and l4dmaps.com