During 2008 I was involved with the development of several Joomla CMS web sites. The Joomla CMS is an open source project available for free usage. You can download it for free, set it on your server and start running your own web site. The Joomla CMS allows managing the web site content via a comfortable web based interface. Based on my experience with Joomla CMS so far, I can testify that using the Joomla CMS hardly requires any software programming experience. In addition, given the clear separationg Joomla CMS has between the data and the look & feel (theme) it is amazingly simple to change a Joomla CMS web site look & feel. An article published at Zuntel website presents the Joomla CMS web sites I was involved with their development during 2008.
The Visitor Design Pattern
The visitor design pattern allows us to add operations to objects that already exist without modifying their classes and without extending them.