ordenar eventos por ordem decrescente

Na tabela wp_posts, os dados estão assim :

/applications/core/interface/imageproxy/imageproxy.php?img=http://www.hugosenna.com.br/wp2/1.jpg&key=af06382647440c9d698fc8ca45bbd932fad733320814f5c30a2823dea749b819" alt="1.jpg" />

/applications/core/interface/imageproxy/imageproxy.php?img=http://www.hugosenna.com.br/wp2/2.jpg&key=336a61309e4bd6ea420fb1260bc2aabf256a06f2f5ef3f8e7c6b801aa87f6d96" alt="2.jpg" />

e quando insiro algum evento, alem dessa tabela acima, vai dados para wp_postmeta, e ficam assim:

/applications/core/interface/imageproxy/imageproxy.php?img=http://www.hugosenna.com.br/wp2/3.jpg&key=006ab735adc4ac6893e970a13e9c152347ba4e96a82db41c15a2fa80a8eaaad7" alt="3.jpg" />

no arquivo que exibe os eventos fica assim:

<div class="latest-events">

 <?php query_posts('post_type=event&posts_per_page=3'); if (have_posts()) : while (have_posts()) : the_post(); ?>

 <article class="latest-event cf">

 <?php if(ale_get_meta('event_date')) { ?>

 <time datetime="2014-08-09" class="date">

 <?php $date_event = ale_get_meta('event_date');

 $date_event_one = explode('/',$date_event); ?>

 <span class="date__day"><?php echo date("d", mktime(0, 0, 0, $date_event_one[0], $date_event_one[1], $date_event_one[2])); ?></span>

 <?php echo date("M", mktime(0, 0, 0, $date_event_one[0], $date_event_one[1], $date_event_one[2])); ?>

 <span class="date__year"><?php echo date("Y", mktime(0, 0, 0, $date_event_one[0], $date_event_one[1], $date_event_one[2])); ?></span>

 </time>

 <!-- End date -->

 <?php } else { ?>

 <time datetime="2014-08-09" class="date">

 <span class="date__day"><?php echo get_the_date('d'); ?></span>

 <?php echo get_the_date('M'); ?>

 <span class="date__year"><?php echo get_the_date('Y'); ?></span>

 </time>

 <!-- End date -->

 <?php } ?>

 <div class="latest-event__wrap">

 <header class="latest-event__header">

 <h1 class="latest-event__title">

 <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>

 </h1>

 <?php $cur_terms = get_the_terms( $post->ID, 'event-category' );

 if($cur_terms != '') { ?>

 <p class="latest-event__category">

 <?php

 foreach($cur_terms as $cur_term){

 echo ' '. $cur_term->name.' ';

 }

 ?>

 </p>

 <?php } ?>

 </header>

 <!-- End event post header -->

 <p><?php trim_content_chars(120,'...') ?></p>

 </div>

 <!-- End event post wrap -->

 <a href="<?php the_permalink(); ?>" class="btn-more">+</a>

 </article>

 <!-- End event post-->

 <?php endwhile; else: ?>

 <?php ale_part('notfound')?>

 <?php endif; wp_reset_query(); ?>

 </div>

 <!-- End Events posts -->

a pergunta é: como exbir os eventos por ordem decrescente, sendo que a data do evento vai para a tabela wp_postmeta , no campo meta_value ?