Version 4.0 of middleman.
Middleman is a static site generator based on Sinatra (a Rails-like Ruby based tool chain). It incorporates dozens of templating languages (Haml, Sass, Compass, Slim, CoffeeScript, and more). It makes minification, compression, cache busting, Yaml data (and more) an easy part of your development cycle.
Typical Development Cycle
This is the typical development cycle with Middleman:
- Run 
middleman init projectname - Start the server with 
middleman server - Modify the files in the directory 
projectnamewhile viewing them in your browser at http://localhost:4567 - When you're happy with the files, run 
middleman build - Copy the generated static files from 
projectname/buildto your webserver 
Having the server available while developing turns out to be critical, as it allows quick review of changes ( For auto-reload, use middleman-livereload gem). This isn't as much of an issue with "normal" static site generators, but when you start adding partials, SCSS, Compass and the other goodies, that Middleman supports, server mode is invaluable.
Resources
- Official site
 - Source code on github
 - Migrating from wordpress to middleman
 - Twitter: @middlemanapp
 - Support: Right here at stackoverflow - use the middleman tag