save random glitch image from flikr's glitches pool to file

glitch.rb

#!/usr/bin/env ruby

require 'nokogiri'
require 'open-uri'

index_url = 'http://www.flickr.com/groups/glitches/pool/'
index = Nokogiri::HTML(open(index_url))

image_urls = index.css('a[class="rapidnofollow"] img').to_a
image_url = image_urls[rand(image_urls.length)]['src']

image = File.open(ARGV.first, 'wb')
image << open(image_url).read