Batflat - Lightweight, fast, easy, and free CMS.
Rubedo - Rubedo is an open source big data CMS & E-commerce with Behavioral targeting.
Grav - The modern open source flat-file CMS
Joomla Video Plus Theme - Video Plus is a free joomla template suitable for building a video sharing website.
WordPress - WordPress is web software you can use to create a beautiful website or blog. We like to say that WordPress is both free and priceless at the same time.
dotCMS - Java-based content management system