GitHub Pages + Octopress + Slash Theme
First, create a Github Pages repository only.
https://pages.github.com
It will do Octopress all other things.
http://octopress.org
Next, Octopress setup, deploy, and blogging.
http://octopress.org/docs/setup/
We have 3rd party Octopress themes.
https://github.com/imathis/octopress/wiki/3rd-Party-Octopress-Themes
This blog changed Slash theme.
https://github.com/tommy351/Octopress-Theme-Slash