(This passage should hint that a special story will accompany this contest. The story will have no effect on the rules, will not be implemented by the contestants, but it will simply make the contest more interesting...)
Here's the thing:
Selecting the Elements
You have an idea about an element that should be present in the game? That element should somehow force the contestants to be considered in the game. It should now be easily implemented into an already existing game. For example, a Pony is a bad element for this purpose, because replacing Horse with Pony is very easy. Distress signal, on the other hand, will alter the gameplay in significant fashion and you cannot easily put Distress signal into an already existing game.
If you have an idea, post it here or preferably post it to me in PM to avoid spoiling the surprise to others.
Altering the rules
Some prototype rules are on display at Four Elements VII so-far-website. If you want to suggest modifications, please do it.
And ne0_kamen, I will send you a PM concerning your offer of help. Thank you.