call-it.js

//duh

$(document).ready(function(){
  $('#recent-activity').tabs();
});

jquery-ui-tabs-html5.html

<!-- and your markup needs to look like: -->

<aside id="tabs">
  <header>
    <h1>News Feeds</h1>
    <nav id="feed-chooser">
      <span><a href="#news-feed">All News</a></span>
      <span><a href="#featured-news-feed">Featured News</a></span>
    </nav>
  </header>
  <ol id="news-feed">
    <li>
      <time class="feed-item-date" datetime="2010-09-24">9/24:</time>
      <header class="feed-item-title">
        <a href="#">Grapes roll into season</a>
      </header>
      <aside class="feed-item-reply-count">
        <a href="#"><span class="num">6</span> replies</a>
      </aside>
    </li>
  </ol>
  <ol id="featured-news-feed">
    <li>
      <time class="feed-item-date" datetime="2010-09-24">9/24:</time>
      <header class="feed-item-title">
        <a href="#">This is featured news instead!</a>
      </header>
      <aside class="feed-item-reply-count">
        <a href="#"><span class="num">6</span> replies</a>
      </aside>
    </li>
  </ol>
</aside>

jquery-ui-tabs-html5.js

//on lines 105 & 106, change:

this.list = this.element.find( "ol,ul" ).eq( 0 );
this.lis = $( " > li:has(a[href])", this.list );

// to:

this.list = this.element.find( "nav" ).eq( 0 );
this.lis = $( " > span:has(a[href])", this.list );

// AND! /!\ Change all instances of "li" to "span"