Here you can find and download scripts of a CMS-based web page. It is not just a template. It is actually a service which you can build from scratch not knowing that the source code even exists! And it's absolutely free!
Latest release: CMS-based service 0.4 with the User management & Discussion Forum (check the "Download" area)
What you need to start is:
A server with PHP and MySQL (single database is enough, so it might be rather a cheap web-host account).
Ideas what to put into your service
Some experience with WYSIWYG editors (such as MS Word or Open Office) would be helpful
