Looking for CMS as SaaS (open source, free)

Question

CMS

Smart people, we need your help. I lost my way with Google and Yandex in search of a suitable solution.
For the sake of studying the basics of this business, so to speak, it is necessary to find a CMS, preferably open-source and free, which acts as a service for people who want to make simple, but functional sites.
At least the average similarity of WebAvant.
The language can be Ruby or PHP.

Please help, thanks in advance for the links.

Thank you for your attention.

Answer 1

Drupal Gardens is clear that on the basis of Drupal
you can wind up simple things.
As far as I know, there will be a report on the topic at the nearest Kiev Camp

Answer 2

ucoz.ru
?

Answer 3

CMS SaaS is, in fact, any blog hosting platform. Learn, wordpress.com.
With classical restrictions on functionality.

Answer 4

Umi recently launched cms as a service, Umi cloud if memory serves

Answer 5

In the near future APIQ CMS will be available as SaaS