Possibilities...
- Users could rate moderators.
Users could rate other players.
Players could rate completed games (maybe this would indirectly result in a moderator's rating).
Moderators could add themselves to the moderator queue, and indicate which sites they would be willing to mod a game on.
Moderators could post the details of their upcoming games as they near the top of the queue.
Players could add themselves to the player queue and indicate which sites they would be willing to play a game on and/or which games they want to play in.
The site could then match moderators, players, and games, based on the queues, send out invitations, and accept confirmations.
Policies of the various boards (number of active games per player, experience required to mod, etc.) could be maintained and enforced.