Quake3World

I know there are some incredible mapper that frquent here, so this should be some good news for you all

http://contest.thinkingwithportals.com/

If I could Hammer I would be all over this, though I might try and Hammer just to design a map and enter..!

Remember Hammer has a steeper learning curve compared to radiant, and scripting takes some time.

I always found hammer much easier and more intuitive than radiant. Maybe because I was older when I got to grips with it.