This is a suggestion to the developers, first like to say well done for all the work on the server - I only recently found it but it is defiantly the most interesting and fun one I have played on in a long time!
I do a bit of programming myself, mostly web app development (Python, Django etc.) and have recently played around with Java for Bukkit plugins.
One idea that I think would really build the immersion of the world would be to have a dynamic sound system. This would mean that a selection of 8 bit (.nbs) sound tracks would be played as you enter a specifically defined area of the map.
I've played around and been able to get a list of Harry Potter sound tracks converted to Minecraft note block sounds (These sound really cool!!), then using world guard defined an area and got the sound track to play within that area.
I think it would be a neat idea for when new players join they get greeted with the Harry Potter sound track! But also within classes and POI's like the Great Hall.
I understand that you are working on a bunch of other ideas, but if any developers are interested It would be cool to see it work / help out in any way.
Thanks for reading,