Drupal 4.7.4 is a Moodle-like open-source Content Management System that has its origins in an ADSL-sharing scheme originally set up by University of Antwerp students Dries Buytaert and Hans Snijder in 2000. According to the official website “The name Drupal, pronounced ‘droo-puhl’, is derived from the English pronunciation of the Dutch word ‘druppel’ which stands for ‘drop'”.
Obviously, being open-source, the basic CMS is free to download. It requires a PHP-capable web server (such as Apache 2.0) running PHP version 4.3.3+, and a PHP-supported Database Server such as MySQL v3.23.17 or newer. All of the system requirements can be viewed here.
I’ll post a comprehemsive review of Drupal once I’ve had a closer look. In the meantime, check out the links for yourself.