First, try to tear yourself away from watching the monkey, and notice that the top ad div has code written in it, with the ad misplaced off to the side. (how its misplaced can change with window resizing). correct placement can be seen with Firefox Bug occurs in r29647 and in 10.5.1 stock Safari.
Created attachment 18536 [details] screenshot
oh, spoofing as firefox 2 fixes the bug
moved to evangelism
I'm unable to reproduce the problem now. Probably the bug is fixed.