help on how to randomize posts

Hey all,

I know this is a big ask bust I am trying to workout how I can randomize the following code (from Justin Tadlock) I have. This code currently pulls a video based on a custom field from a post. What I would dearly love is for the script to randomize any posts that has the custom field. I have been searching high and low but as of yet have found no tutorial.

Can anyone help please?

Thank you

‘
<?php
// This file displays the latest video article on the front page
rewind_posts();
// Query one post from “video” category
$my_query = new WP_Query(‘category_name=video&showposts=1’);
while ($my_query->have_posts()) : $my_query->the_post();
// Get the “Video” custom field Key as an array (displays single Value in the video block)
$video = get_post_custom_values($key = ‘video-value’);
?>

<h5>” title=”<?php the_title(); ?>”><?php the_title(); ?></h5>

<div class=”<?php echo $i; ?>video”>
<div>
<?php
// Check to see if custom field “Video” is set and if it has anything in the “Value” field.
if(isset($video[0]) && strcmp($video[0],”)!= 0) {
// Display valid XHTML player for YouTube, Google, MetaCafe, and other video sites
// “echo $video[0];” displays the first item in the array for the custom field “Video”
?>

<object type=”application/x-shockwave-flash” data=”<?php echo $video[0]; ?>” style=”width: 290px; height: 242px; border: none; padding: 0; margin: 0;” id=”video-block-<?php echo $i; ?>”>
<param name=”movie” value=”<?php echo $video[0]; ?>” />
<param name=’wmode’ value=’transparent’ />
<param name=”quality” value=”best” />
<param name=”bgcolor” value=”transparent” />
<param name=”FlashVars” value=”playerMode=embedded” />
</object>

<?php } // endif

// If there is no Value for the custom field Key “Video”
else {

// echo error checking to check custom field errors
echo ‘Did not add a video URL to the custom field Key of “Video”‘;
echo ‘<!– This user did not add the video URL to the correct custom field –>’;

} // endelse
?>
</div>
</div> <!– video –>
‘