I know I am not active on the MC servers, but I still feel I should drop in from nowhere to suggest this, as it REALLY is an interesting mod to play. So why not do it online, with other players? And this surely would make ME more active :P
So what I think would be great, is if you made one of the servers, into a "Desert surviving" server. Basically, this is a type of game play where you try to survive in a desert. I suggest you watch this video, and see for yourself what it's like, as these guys explains how the game mode works out and how to stay alive.