This is for Blaine

app.rb

require 'open-uri'
require 'sinatra'
require 'nokogiri'
require 'yajl'

class MedalScraper
  def initialize
    @data = []
    html  = open('http://www.london2012.com/medals/')
    doc   = Nokogiri::HTML(html)

    doc.css('.historicalMedals tbody tr').each do |tr|
      @data << {
        :country => cell(tr, 1),
        :gold    => cell(tr, 2),
        :silver  => cell(tr, 3),
        :bronze  => cell(tr, 4),
        :total   => cell(tr, 6) # the fifth cell is skipped because it is a hidden meta-cell
      }
    end
  end

  def json
    Yajl.dump @data
  end

  private

  def cell(tr, idx)
    node = tr.css("td:nth-child(#{ idx })")
    node.inner_html.gsub(/\s+/, '')
  end
end

class App < Sinatra::Base
  get '/' do
    content_type :json
    MedalScraper.new.json
  end
end

config.ru

require './app'

run App

Gemfile

source 'http://rubygems.org'

gem 'nokogiri'
gem 'shotgun'
gem 'sinatra'
gem 'yajl-ruby'