Hmm. I see two backgrounds, an "inner" background and an "outer" background. I think the site would look a bit more compelling with a single background - it'd look more like a single cohesive website that way, while right now it looks a bit more like one website inside another website.
As for the borders, I think pure white is a bit too bright for it. The most important part of your website should be the content (in this case, the text). That should be pure white. The other stuff would probably look better as grey.
The sidebar menu doesn't look that much like a menu - it looks kind of like a list of text, at least until you move your mouse over it. I do like the mouseover effect, though.
Those are my thoughts on design.
The menu looks a bit long, as well. 16 items - that's a bit much to have in a flat list. Maybe categorize them, or merge them, or something?
Well, we got IPB back when this board was more active, so our current activity doesn't really reflect the conditions in which we got IPB. We have a few projects in the works that should renew recruitment.