An idea
You could have as many people as are interested. My original idea involved having each of the participants provide one of the outlines, but in reality, the general community could provide them.
It would require strict guidelines as to what could and couldn’t be in the guideline, and the participants could vote to include or exclude a particular outline.
For example, some of the rules could be:
These basic questions must be answered: who, what, where and why.
1.The outline may not include the main character’s gender, or any physical feature (ie… height). It must include a general description of who they are, with one specific characteristic (ie… an uptight twenty five year old mechanic that works on motorcycles)
2. The outline must give a general idea of why they’re there, what they’re trying to accomplish, and any limiting circumstances.
3. The outline must include a place, but not a particular location. (an amusement park is OK, but Disney’s Magic Kingdom is not.)
4. The purpose of the outline is not to provide the story, but to provide specific elements that constrain the direction of the story.
5. Options can be included, that would give the author the ability to take the story in one of several directions limited by the choices.
This is an off the cuff example of what some of the rules could be. I certainly forgot something in this, so by all means help me out here. 
An example of an outline following the above rules would be:
Premise: The character decides they need to relax so it’s time for a vacation and books a cruise. During the cruise, they meet a person that really interests them. In the process of getting to know each other, the person is determined to get the character to relax.
Main Character: a high strung, thirty year old air traffic controller.
Location: Cruise ship.
- Character makes his way to the ship and finds his cabin.
- Meets person at dinner the first night.
- They agree to spend the next day on an excursion off ship
- They find they’re really attracted to each other, and end up spending the night together.
- The next day, the person takes the plunge and explains that they’re an AB.
- OPTION. Either the person convinces the Character to try this, or the Character enjoys caring for the person.
- Resolution
Again, this is an example. Feel free to point out any problems you see with any of this.
The resulting stories could be judged not just for content, but also how well they followed the outline.
Thanks,
BabyButt