Moodle is a Course Management System (CMS), also known as a Learning Management System (LMS) – a free Open Source software package designed to help educators create effective online courses based on sound pedagogical principles. Moodle can be installed on any computer that can run PHP, and can support an SQL type database.
Moodle can scale from a single-teacher site to a 200,000-student University. Moodle is provided freely as Open Source software. It can be extended with moodles and plugins, also it has different language packs. You can change the look and feel with themes.