inkofdeath230 posted a video of the Nova Prospekt Map from Half Life 2 for Left4Dead. The map was uploaded by eodwjfj.
You can download the map from here: http://www.garrysmod.org/downloads/?a=view&id=60508
Looks like a blast! Thanks guys ...
Update: Just gave the map a quick playtest and it was great fun.
For some reason sv_cheats changes to 1 at the crescendo event - not quite sure why. The area that I had the most problem with was the water because there are underwater pipes that you have to jump over and that is quite awkward ... otherwise it's a great map to reminise!
Now we just need Ravenholm!