Moodle

Moodle (abbreviation for Modular Object-Oriented Dynamic Learning Environment) is a free source e-learning software platform, also known as a Course Management System, Learning Management System, or Virtual Learning Environment (VLE). As of October 2012 it had a user base of 70,793 registered and verified sites, serving 63,204,814 users in 6.7+ million courses with 1.2+ million teachers.