Open source full-featured Content Management System for web sites. Web server with MySQL database required for installation.

• Joomla.org
• Sample sites
  
  • Eastern Montana WELS
  • Grace Lutheran in Portland, OR
  • Cornerstone

PROS

• Larest installation base of open-source CMS software
• A huge library of modules for customization

CONS

• Doesn't have a lot of layers of categorization (taxonomies)
• Must have a plan for ongoing maintenance/backups/upgrades

ADDITIONAL COMMENTS/CONTACTS

• Joomla extensions - extensions.joomla.org/
• Joomla documentation - docs.joomla.org/