jamesoakley

I was able to accomplish this through two steps:
1- Modify wordpress query.php to support adding a new parameter to the query string.
2- Use php to calculate the new delayed time.

Step 1:

Open wp-includes/query.php and search for this line:

if ( $q['w'] )
			$where .= " AND WEEK($wpdb->posts.post_date, 1)='" . $q['w'] . "'";

and replace it with:

if ( $q['w'] )
			$where .= " AND WEEK($wpdb->posts.post_date, 1)='" . $q['w'] . "'";

		if ( $q['before'] )
			$where .= " AND $wpdb->posts.post_date < '" . $q['before'] . "'";

Step 2:

Here is my php function strtotime (check http://php.net/strtotime) to calculate the 2 hours delay time:
$unix_delayed_time = date(strtotime("-120 minutes"));

then I convert the unix timestamp generated by strtotime into a normal Mysql date format using:
$delayed_time = date("Y-n-j G:i:s", $unix_delayed_time);

then I used it in a loop:

query_posts('cat=3&before=$delayed_time');

// the Loop
while (have_posts()) : the_post();
  // the content of the post
  the_content('Read the full post »');
endwhile;

So the total code is:

<?php
$unix_delayed_time = date(strtotime("-120 minutes"));
$delayed_time = date("Y-n-j G:i:s", $unix_delayed_time);
query_posts('cat=3&before=$delayed_time');

// the Loop
while (have_posts()) : the_post();
  // the content of the post
  the_content('Read the full post »');
endwhile;
?>