Found this very cool open-source poject in my travels a while back. Limbo is a content management system written in PHP and based on the wery popular Mambo CMS. The big difference with Limbo (or Mambo Lite as some call it) is that it will run without requiring a database. It uses text files stored on the webserver as the database. This means you can run a very professional looking CMS-based website without requiring database hosting (this means cheaper). Supports nearly all the functionality of it’s larger brother and can even use the same templates. Although it’s still in the early stages of development, what has been accomplished so far and the functionality available is very impressive. It has an administration interface where you can configure the site and supports user registration and assigning of permissions to contributing authors.
Check out my test install.