Joomla is a CMS (content management system) that is open source and customizable enough to run personal homepages or power corporate websites.
The problem with most open source offerings is you often have to know quite a bit of code before you can jump into changing the look and feel. If you are interested in Joomla, Joomla Templates is a book detailing how to create a Joomla template in five easy steps. I do a fair amount of PHP / MySql work and even though the framework for each is free, having a step by step guide on hand is worth shelling out some money.
The Joomla templates book is available for download as soon as you make your payment so you don't have to wait on the UPS man. You can tear right in and start learning from the 91 page PDF. With the book purchase, you also get access to over 40 prebuilt templates for free as well as step by step instructions for building single column, two column and three column templates. As a paid member, you also get access to a cloud module. A "Tag Cloud" takes a list of your most popular articles and displays them as a cloud, the more popular an item is the bigger the link is to it