Maybe I'm overlooking something, but what are they using to get the upper rounded border in the div class="main-wrapper" section, that crosses the fiverr logo thru the center. I increased the margin of that class in firebug and the "image?" sits in the margin while the entire div moves down. I don't see a div or image for that element. All the the other rounded elements have an associated image. Also, they seem to have a jquery rounded border library (corner.js) but I don't believe its being used.
It's part of the background for the main-area div (bg-header.png). Wow, they have both an id and a class called "main-wrapper". Check out main.js, they have used jquery corners for lots of things, like those tiny "order now" links on the right.