Monthly Mini Golf in The Nineteenth Byte
Every month, we could hold an event in TNB which lasts an hour or two. CMCs could be drafted ahead of time (or during the event), and through some method we could choose which ones are posted when (or just make it a free for all).
We could optionally also have some sort of scoring, where the person who wins the most CMCs would be the winner and potentially get a bounty.
This would be a fun introduction for some users to TNB or even CGCC as a whole, and for users who are already active it could be a fun event to build the community.
I don't think the clutter would be too much of a concern; other sites have similar events in their main chat rooms, and this is about as on topic as we can get. The events feature would advertise the event a little ahead of time, and users could register for it (which isn't required, but notifies them when it's about to start).