Building a customized version of Ubuntu could be very useful. For example it could be used to provide
1. a customized interface language (such as Arabic).
2. customized applications such as Quran, Arabic encyclopaedias, dictionaries.
3. customized art works (backgrounds, icons, themes).
4. customized drivers.
Fortunately, building such CD is made very easy with UCK (Ubuntu Customization Kit). I used this tool back in 2006 to build Arabic Edition of Ubuntu. I reported the method in iraqilinux.org back then, but as the site is closed now :( I think, reporting it again wouldn't hurt.
Of course, now, I customized the latest version Ubuntu, Ubuntu Intrepid Ibex 8.10. Although it is little dated, the following tutorial is very helpful for building a customized version of Ubuntu: https://help.ubuntu.com/community/LiveCDCustomization
Here is screenshot of my version:
