CiviCRM is a Constituent Management system. (Think CRM but with membership and event planning included) Mostly focused on Non-profit or membership based organizations. CiviCRM can be integrated into Joomla or Drupal.

It would be nice to see a Jumpbox of CiviCRM stand-alone, CiviCRM+Joomla, and CiviCRM+Drupal!

Details on CiviCRM: http://civicrm.org/