In 2006, I built and hosted a custom CMS in ASP for the Colorado Healthcare Information and Management Systems Society. It featured a slick front-end using web fonts and configurable flash animations. The back-end tool allowed for basic but simple configurations:

I even included a batch mailing tool, with timers built-in to be a good email citizen.

CMS were an emergent property of web design in those days. Everybody spontaneously started coding something like this, and while mine never got anywhere close to what we use today, it was a good all-around exercise in software development.