<ul id="nav2" class="clearfloat">
            <li><a href="<?php echo get_option('home'); ?>/" class="on">Home</a></li>
            <?php wp_list_categories('orderby=name&exlude=181&title_li=');
            $this_category = get_category($cat);
            if (get_category_children($this_category->cat_ID) != "") {
                    echo "<ul>";
    wp_list_categories('orderby=id&show_count=0&title_li=&use_desc_for_title=1&child_of='.$this_category->cat_ID);
                    echo "</ul>";
            }
            ?>
    </ul>