could I put this in my header template to randomize adsense+my own banner .gif?

[SeanThomps]

I want to randomly display my adsense script and a banner or two. Could I insert something like this into my header template:

<?php
$number=mt_rand(1, 2);
if ($number==1) 
{
include "http://www.volconvo.com/adsense.txt"; 
}
else
{
include "http://www.volconvo.com/banners.txt"; 
}
?>

With those .txt files full of their respective codes...

Or would you do something else?