Rules are being refined at the moment I suspect.  Cardinal Bryster has been burning the midnight oil refining all those past concerns. 

Not wanting to take any of his job I will say, in the past the contest specific focus will be stated in a thread by the previous winner.  (that is the only prize) The thread will usually be made a sticky.

Once the desires of the previous winner is honed to a workable and understandable goal, the mod(s) will post the official guidelines.

The generic rules are all available by looking at those links at the top of this forum page.