As suggested by nbohr1more, we've still got time for a very short, focused Halloween contest.
I hereby propose the following rules:
- Make the mission public on Halloween (31 October, Saturday).
- Prefabs and modules are okay, but don't just relabel a fully built mission you have worked on for five years and call it a submission.
- There is no rule 3.
The deadline should make things neat, simple and focused. Don't build your dream mission (although feel free to build your worst nightmare!), because you won't finish in time. Build incrementally, and focus on getting something short and simple out the door.
 I don't know how to turn the poll results public, so please let it be known you are participating. I am participating!