Open Source CMS platforms

Following up the good response to the "Open Source Social Networking Platforms", I am back with a list of CMS platforms. If only CMS platforms were as simple as SNS platforms. There are way too many. Not very surprising considering the broad definition of content and the broad applications they are used in. I present here a small list of Open Source CMS platforms, without bothering about all the commercial ones.

At the end of this post, I provide a few links which give you more information than what I mention here.

Open Source

Open Source CMS (The name says it all, the best of all lists)
e-Learning (CMS for developing educational content)
Making a Better Open Source CMS
sex, lies and CMS Vendors (Clearing the Myths)

If you have used any of the above, please leave your experiences in the comments.