ImpressPages is an open source CMS application where you can create and edit while browsing.

Creating new themes requires only the knowledge of HTML-CSS and with the help of a drag 'n' drop interface, texts, videos, photos (or photo galleries) and even forms can be inserted quickly + positioned as you wish.

FUEL CMS is a modular-based hybrid of a framework and a content management system. It's developed on the popular CodeIgniter PHP web framework and allows you to create your models, views and controllers like normal and only use the CMS part when and if you need it.

Hotaru CMS is an open source, PHP platform for building your own websites. With flexible plugins and themes, you can make any site you like. For developers, Hotaru CMS includes an extensible Admin CP, a powerful plugin system and a unique override feature for designing custom themes. There are dozens of built-in class libraries and some popular 3rd party scripts including ezSQL, htmLawed, Inspekt, JSMin, and SimplePie.  Hotaru CMS can be used under the terms of the General Public License v.3

Oxwall is an open source application, built with PHP-MySQL for creating a full-featured social network.

It enables users to create groups, events, blogs or forums, upload photos and videos, comment or tag any content and much more.

Lightweight, themeable and dynamic, PyroCMS is perfect for CodeIgniter developers to kickstart your projects.

Have no idea what the first paragraph means? No worries! PyroCMS is not just for us nerdy developers; it can be used by anyone.