Here's the breakdown:
- Get a Facebook account and login to it.
 - Add Facebook's Developer application to your profile.
 - Go through the motions of creating an application with Facebook which is really nothing more than a registration process of sorts.
 - If you understand the Anatomy of a Facebook Application then you know that the two most important components for creating/registering an application in/with Facebook are:
 - Callback Url
 - Canvas Page URL
 - Get XAMPP. (I know the site looks shady but I'm not their UI guy.)
 - If you don't have a domain name, simply login to your home router and figure out your real IP address.
 - Edit your router's Port Forwarding settings to allow connections from the outside world to come in to your computer at port 80.
 - Startup Apache from your XAMPP install and perform a quick sanity test to see if you can access the default web site.
 - Take the source for a default index.php page provided by Facebook and throw it onto your machine and point your Apache's httpd.conf file to it. Also throw down 3 more PHP files that make up the Facebook client libraries.