Custom Post Type ‘Event’: Chronological list of recurring events from meta_values in array

Here’s the code that finally worked for me:

<?php 
global $events_meta_termine;
$today = getdate();
$my_query = new WP_Query('post_type=events&posts_per_page=-1&monthnum='.$today["mon"]);
$events=array();
while ($my_query->have_posts()) : $my_query->the_post();
    $do_not_duplicate = $post->ID;
    $meta = get_post_meta(get_the_ID(), $events_meta_termine->get_the_id(), TRUE);
    foreach ($meta['termin_group'] as $termin)
    { 
        $event=array();
        $event['title']=get_the_title();
        $event['date']=$termin['termin_date'];
        $event['time']=$termin['termin_time'];
        $event['location']=$termin['termin_location'];
        $events[]=$event;
    } 
endwhile; 
wp_reset_query();

$i=0;
usort($events, "cmp"); 
function cmp($a, $b){ 
return strcmp($a['date'],$b['date']); 
} ?>

<table>
<?php $current_month="";
 foreach ($events as $event){   
     if ($current_month!=mysql2date('F Y', $event['date'], true))
     {
         $current_month=mysql2date('F Y', $event['date'], true);
         echo '<tr><td colspan="5">'.$current_month.'</td></tr>';
     } ?>
    <tr>
      <td><?php echo $event['title']; ?></td>
      <td><?php echo mysql2date('D', $event['date'], true); ?></td>
      <td><?php echo mysql2date('j. F Y', $event['date'], true); ?></td>
      <td><?php echo $event['time']; ?> Uhr</td>
      <td><?php echo $event['location']; ?></td>
    </tr>
<?php } ?>
</table>