Ordinalized Dates in Jekyll

ordinalized_date.rb

require 'date'

module Jekyll
  module OrdinalizedDate
    def ordinalized_date(input)
      d = input.strftime("%e")
      input.strftime("%A ") + self.ordinalize(d.to_i) + input.strftime(" %B, %Y")
    end
    def ordinalize(number)
      if (11..13).include?(number % 100)
        "#{number}<sup>th</sup>"
      else
        case number % 10
          when 1; "#{number}<sup>st</sup>"
          when 2; "#{number}<sup>nd</sup>"
          when 3; "#{number}<sup>rd</sup>"
          else    "#{number}<sup>th</sup>"
        end
      end
    end
  end
end

Liquid::Template.register_filter(Jekyll::OrdinalizedDate)

post.html

---
layout: default
---
<h2>{{ page.title }}</h2>
<p class="meta">{{ page.date | ordinalized_date }}</p>

<div class="post">
{{ content }}
</div>