N1ED is an add-on for CKEditor and TinyMCE that completely redefines your vision of WYSIWYG editors. Absolutely FREE. Auto update from CDN.
Editor.js is a block-styled editor for rich media stories. It outputs clean data in JSON instead of heavy HTML-markup. And more important thing is that Editor.js is designed to be API extendable and pluggable.
Docutils is an open-source text processing system for processing plaintext documentation into useful formats, such as HTML, LaTeX, man-pages, open-document or XML. It includes reStructuredText, the easy to read, easy to use, what-you-see-is-what-you-get plaintext markup language.