Bolt Wire

BoltWire - http://www.boltwire.com/ - started out as a wiki (its roots is as a plug-in to PmWiki) but quickly went far beyond the typical wiki.

It allows you to create member accounts and member groups instantly (like a content management system). It can input, manipulate, and save data, then output fully formatted reports (like a database). It has a built in site indexing system that allows you to find and retrieve information on your site in seconds (like a search engine). Plus, with easy-to-install plugins, you can instantly set up forums and blogs, manage newsletters, do real-time chat or instant messaging, run e-commerce, give self-grading quizzes, publish RSS, and more. BoltWire, in short, is a complete web development solution.

BoltWire is a flatfile system (no database).