If you are a game development enthusiast/hobbyist/indie like me, you've probably heard of UDK. If not, get out from under that rock and head staright to http://www.udk.com. It's pretty much an Indies dream come true.
I've been using it since early November and its a hell of a steep learning curve but at the end of the day, its Unreal. I've joined a small indie team as an Unreal Scripter to work on a project called Nothern Island 1983.
The feature list is very impressive, including speed tree, face fx, the unreal editor in all its glory, documentation via the UDN and recently released video tutorials. Christmas really did come early this year and the Indie(read me) has to stop making excuses.