This code will change the order in which categories are displayed in the top bar. The default order is like this:

Directory » Category » Sub-Category

This mod will make the path display as:

Sub-Category « Category « Directory

Open topbar.tpl and find this code:

  {* Display current path *}
  {assign var="current_path" value=""}
  {foreach from=$path item=cat name=path}
      {assign var="current_path" value="`$current_path``$cat.TITLE_URL`/"}
      {if !$smarty.foreach.path.first} » {/if}
      {if !$smarty.foreach.path.last}
        <a href="/{if smarty.const.ENABLE_REWRITE}{$current_path}{else}index.php?c={$cat.ID}{/if}">{$cat.TITLE|escape|trim}</a>
      {else}
        {$cat.TITLE|escape|trim}
      {/if}
  {/foreach}

Replace it with this code:

{* Display current path in reverse *}
{assign var="current_path" value=""}
{section name=foo loop=$path step=-1}
  {assign var="current_path" value="`$current_path``$path[foo].TITLE_URL`/"}
  {if !$smarty.section.foo.first}
    « <a href="/{if $smarty.const.ENABLE_REWRITE}{$current_path}{else}index.php?c={$path[foo].ID}{/if}">{$path[foo].TITLE|escape|trim}</a>
  {else}
    {$path[foo].TITLE|escape|trim}
  {/if}
{/section}