groups.json

{
  'groups': [
    {
      'id': 1,
      'name': 'jQuery Team',
      'children': [
        {
          'id': 2,
          'name': 'John Resig'
        },
        {
          'id': 3,
          'name': 'Dave Methvin'
        },
        {
          'id': 4,
          'name': 'Yehuda Katz'
        },
        {
          'id': 5,
          'name': 'Julian Aubourg'
        },
        {
          'id': 6,
          'name': 'Anton Matzneller'
        }
      ]
    },
    {
      'id': 7,
      'name': 'jQuery UI Team',
      'children': [
        {
          'id': 8,
          'name': 'Richard Worth'
        },
        {
          'id': 9,
          'name': 'Scott González'
        },
        {
          'id': 10,
          'name': 'Jörn Zaefferer'
        },
        {
          'id': 11,
          'name': 'Todd Parker'
        },
        {
          'id': 12,
          'name': 'Adam Sontag'
        }

      ]
    }
  ]
}

template.html

<script id="category-template" type="text/x-jquery-tmpl">
  {{if groups.length}}

    {{each groups}}
      <li data-catId="${id}">

        {{tmpl($value) '#category-content-template'}}

        {{if children}}
          <ul class="category-child" data-catId="${id}">
            {{each children}}
              <li data-catId="${id}">{{tmpl($value) '#category-content-template'}}</li>
            {{/each}}
          </ul>
        {{/if}}

      </li>
    {{/each}}

  {{else}}

    <li>No categories available.</li>

  {{/if}}
</script>

<script id="category-content-template" type="text/x-jquery-tmpl">
  <a href="#">${name}</a>
  {{if children}}
    <span class="ui-li-count">${children.length}</span>
  {{/if}}
</script>