Wordpress random posts in front page



I’d like to have certain posts (defined by category, tag, whatever is best) to randomly appear among my usual blog posts on the Wordpress front page. To make it a bit clearer – I’d like to have these posts serve as random ads mixed with regular non-ad posts.

I was able to have ALL my posts appear randomly by inserting this line on top of my index.php file (found in one of the topics on the Wordpress support forum):

<?php query_posts($query_string . ‘&orderby=rand’) ?>

but I’d only like certain posts to behave that way.

Unfortunately I don’t know php, but it seems to me that the easiest way to achieve this is to have this in my index.php

<?php query_posts($query_string . ‘&orderby=rand’) ?>

only with the added condition that it applies to posts assigned to specific category/tag. Unfortunately I don’t know how such a condition can be added in php, so any help will be highly appreciated.

You can have a you look at my test page here http://athenagfx.com/philoxeniatest

Thank You