Consider the following HTML for a tabbed menu:
<ul id="nav-tabs">
<li class="active">Blah</li>
<li>tab 2</li>
<li>tab 3</li>
<li>tab 4</li>
<li>tab 5</li>
</ul>
Not sure if this is doable, but I want to get the shape of the tabs to look like this with border-radius. no images. The top part is easy, but the bottom, how it curves out on the line is the part I don’t know if it’s possible:

Here’s the jsfiddle
Posting comment as answer…
Chris Coyier has an article addressing this: Tabs with Round Out Borders.
His implementation is a little different than yours, but by playing with the
border-radiusyou should be able to get the effect closer to what you have in your image, though I doubt you’ll be able to get the shadow working (if you prove me wrong, post your code here. Would be very interesting).