Crawler for downloading rails-cast videos

get_rails_casts.rb

 require 'rubygems'
 require 'hpricot'
 require 'open-uri'
 
 class GetRailsCasts
   def initialize
     @host = "http://railscasts.com/episodes/"
   end
   def start
     1.upto(231){ |eps|
       @esp = Hpricot(open("#{@host}#{eps}")) rescue nil
       if @esp
         `cd /path/to/your/dir; wget #{(@esp/".download/a").first[:href]}`
       end
     }
   end
 end