PyroCMS is an awesome, open source content management system built on CodeIgniter.
PyroCMS, like other content management systems (CMS') allows non-technical website administrators to maintain and manage thier websites on a day-to-day basis without requiring the help of a web designer, thus reducing costs.
PyroCMS takes blows away a typical CMS; it's architectured to build scalable web applications. PyroCMS isn't even limited to these amazing features:
It's used by individuals, small & medium size businesses and large organisations worldwide, has an active community and is constantly evolving.