I think it would be great if we have monthly challenges. It could be things that take from a few hours to a weekend.
It should be mostly about crazy ideas, and making something you normally won't.
For example
-a vertical map -a surf map -one room with exactly 200 props -every brush should be a moving entity -100 headcrabs -no lights, only flashlight -a map where you fall down and have to dodge object -a basic floor plan, where we stack them later to make one map -a map under a 45deg angle -a 4 player co-op map
who's with me?