I think its the long url in the New Fan Work post in the Latest Posts box. This post should knock it off that one the list, so let's see if I fix it.
EDIT:
I was right. The border has shrunk but not completely gone away becuase the Puzzle Bobble link overflows as well, though not nearly as much. I've run to this same problem with scrolling divs before. I seem to recall I had to put the scrolling div (the one with "overflow: scroll" css property) inside a div of specific size that did not scroll.
Of course, I was against the Latest Posts block since the beginning, so completely removing it also solves the problem.
