Maybe in regard to "who decides the topic" there are months when there is a certain theme/genre (e.g. romance in February and horror in October) and others when it is wide open for the previous winner to decide what the challenge will be. During a 'genre month' then the winner can still think up some different ideas within the set theme, for example in February there could be challenges such as:
- Love at first sight
- Happily ever after
- Happiest day of their lives
- Unrequited love
- Vulcan Love Slave (aka clean up crew to the holodeck)
- Starfleet Cadet alien STD advisory
Ok some of those may not be workable (or postable on TrekBBS), but limitations can give way to creativity--even when thinking up what the new topic might be.
There could be six of each, so some months we have a rough idea what we'll be faced with and others will be limited only by the winners imagination.