activate and filter by last item in wp_list_categories ?

http://ima-mfa.hunter.cuny.edu/current-courses/
On the site above, I’d like to make sure that the last category gets the class “active” so that when the page loads, those items are shown first. Here is my code:

<ul id="filters" class="clearfix">
<?php wp_list_categories(array('show_option_all' => 'Show All Courses', 'orderby' => 'ID', 'order' =>'ASC', 'title_li' => '', 'taxonomy' => 'course_semester', 'walker' => new Works_Walker())); ?>