controller.rb

  
  # ref: http://bit.ly/fN2ep8
  # http://twitpic.com/3rr8dk
  def sass_colors
    engine= Sass::Engine.new(File.read("app/stylesheets/_colors.scss"), :syntax => :scss, :load_paths => ["app/stylesheets"])
    environment= Sass::Environment.new
    visitor = Sass::Tree::Visitors::Perform.new(environment)
    engine.to_tree.children.each do | node |
      next unless node.kind_of? Sass::Tree::VariableNode
      visitor.send(:visit, node)
    end

    @sass_vars= environment.instance_variable_get("@vars").reject{|k| k == "important"  }
  end

sass_colors.html.haml

%h2 SASS Colors

%table
  %tr
    %th Variable
    %th Color

  - @sass_vars.each do |var|
    %tr
      %td= "#{var[0]}: #{var[1]}"
      %td{:style => "background-color:#{var[1]};width:80%;height:32px;"}