Random posts in sidebar

Hi. Based on the get_posts() documentation on the Codex, I’m trying to create a simple sidebar widget to list 5 random posts from the blog’s archives. My code is as follows:

function widget_from_the_archives($args) {
  extract($args);
?>
  <?php echo $before_widget; ?>
  <?php echo $before_title . "From the archives" . $after_title; ?>
  <ul>
    <?php
      $rand_posts = get_posts("numberposts=5&orderby=rand");
      foreach( $rand_posts as $post ) :
        setup_postdata($post);
    ?>
      <li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
    <?php endforeach; ?>
    </ul>
  <?php echo $after_widget; ?>
<?php
}

Problem is, this code selects the same post 5 times. Am I doing something wrong? The code seems pretty straightforward, but it’s not working for me. Please let me know if I’m missing something obvious.

Thanks in advance,
Richa Avasthi