SiteCake is an easy to use, downloadable CMS (Content Managament System) with a WYSIWYG, in-place, drag & drop editor. A standard web hosting (web server and PHP 5.3+) is all you need to install and use it.
A new, SiteCake-based web site could be created using SiteCake themes. Every SiteCake theme is a plain static HTML site with few extra markups (special CSS class names) for editable regions within an HTML page.
More details could be found here.