Random Selection through PHP

[Maverick]

To start with, I am finally learning the right way to build sites using .php rather than the FP that us old lazy guys relied on. I am planning on completely redoing my sites from scratch.
Question is this. I am planning on setting up a php-file (moviegalleries.php) that will contain hundreds of movie galleries - in this case, asian content.
I am planning on calling that php file into different areas of the asian site but only want to show 10 randomly selected galleries from the moviegalleries.php to be inserted at any one time.

So, this would go into where I want the placement:
<?php include("moviegalleries.php"); ?>

To be perfectly honest, I have read through the PHP manual and W3C Schools and they seem to talk around what I want to do but do not seem to get there ... or perhaps it is simply an aging mind.

How do I actually set up the moviegalleries.php file so it randomly selects the galleries?

Thanks tons.
Mav