CCC is built on top of Protovis, a JavaScript library that allows you to produce visualizations just based on simple marks, such as bars, dots, and lines, among others, which are created through dynamic properties based on the data to be represented. You can get more information on this at: http://mbostock.github.io/protovis/.
If you want to extend charts with some elements that are not available you can, but it would be useful to have an idea about how Protovis works. CCC has a great website, http://www.webdetails.pt/ctools/ccc/, where you can see some samples including the source code. On the page, you can edit the code, change some properties, and click the Apply button. If the code is valid, you will see your chart update. As well as that, it provides documentation for almost all of the properties and options that CCC makes available.
