Open source tools for eBook creation

A quick post with links to resources for creating eBooks with open source software. For my own reference as much as to share with everyone...

This is the most interesting one, perhaps. Something you run on your own web server, and allows for collaborative, online book creation. Exports the finalized product to many different formats. No need to install anything on the user's computer, or restrict what they use.
"The open source platform to help you write and publish print and digital books.
Booktype makes it easier for people and organisations to collate, organise, edit and publish books. Delivering frictionlessly to print, third party services via an API and almost any ereader, Booktype facilitates collaborative production processes. No more lost manuscripts, overwritten Word files, awkward wikis or cumbersome CMSes."

LibreOffice plus eLAIX extension
Cross-platform, very low learning curve. You can quite easily create an ePub from anything you can open with LibreOffice Writer.
Interestingly, eLAIX is actually an expanded version of ePub, made for integration into Learning Management Systems, such as Moodle. Could be worth exploring.

Sigil ePub Editor
Cross-platform ePub creator/editor. You can start from scratch or by importing existing ePub or HTML files.
I can see this also being used as the finishing step after using LibreOffice for text input.

Calibre ebook manager and converter
More of an ebook manager, it can also convert from Word 2007, TXT, ODT, and even PDF (not the best idea!) to ePub or Mobi ebook formats.

If you know of more options, share in the comments!