Markdown + syntax highlighting. Can’t remember where I stole this from. Probably one of the GitHub folk.

markdown.rb

gem 'redcarpet'
gem 'albino' # requires pgyments
gem 'nokogiri'


def markdown(text)
  options = [
    :autolink, :fenced_code, :filter_html, :gh_blockcode, :hard_wrap
    :no_intraemphasis, :strikethrough, :tables, :xhtml
  ]
  syntax_highlighter(Redcarpet.new(text, *options).to_html.html_safe)
end


def syntax_highlighter(html)
  doc = Nokogiri::HTML(html)
  doc.search("//pre[@lang]").each do |pre|
    pre.replace Albino.colorize(pre.text.rstrip, pre[:lang])
  end
  doc.to_s
end