Dillinger is a cloud-enabled, mobile-ready, offline-storage, AngularJS powered HTML5 Markdown editor.
Type some Markdown on the left
See HTML in the right
You can also:
Import and save files from GitHub, Dropbox, Google Drive and One Drive
Drag and drop files into Dillinger
Export documents as Markdown, HTML and PDF
100% open source on GitHub and free of rights (MIT licence).
You can host you own version.