Templation is an extremely lightweight web framework oriented towards content-driven sites. The core idea is to allow elements to cascade down through the directory structure, so that repeated elements only need exist in one place and can be customized easily in specific instances. The ultimate goal is that each file in your document root only contain the content for that single page; the global elements will all be specified by a template and implicitly built according to where the requested page exists within the hierarchy.
Templates
The first design decision of Templation was that every page should be built from a template. After years of wasted effort with server-side includes for headers and footers this seemed a no-brainer. We're not talking complicated templates; just (X)HTML documents with space reserved for content, navigation and anything else that varies from page to page.
Web Hierarchy
Ever notice that web pages in the same directory tend to be more similar than ones in different directories? Seems obvious, but that small observation is the root of Templation's power. Define something in a directory and it automatically applies all pages in that directory (and subdirectories). Of course you can override things at a lower directory. Templation brings the beauty of the cascade to all aspects of your site (not just CSS anymore baby!).
Widgets
Templation templates only support 3 kinds of tags, but the slack is taken up by the all-important widget tag. A widget is just a chunk of PHP code that builds some output based on its location in the hierarchy. Templation's flagship tpl_nav.php widget builds your navigation, unlinks the current page, and will even create nested navigation if requested.
HTML Friendly
Who wants to learn yet another language for creating web pages? You've spent years perfecting your craft using core web technologies. Templation is controlled entirely via html meta tags so you're in comfortable territory from the start.
Design Management
Templation is not a content management system. That term implies a sort of 'web design for dummies' approach that forces the designers to wrestle with new, complicated, and limiting frameworks for constructing websites. Templation is a tool written to empower the designer in recognition of the fact that marking up the actual content is the easy part. The hard part is managing design and navigation changes over hundreds of pages while keeping your web applications functionally integrated. Templation does what it can without getting in your way.