Hi,
just for fun I wanna share this oneliner which prints you the external 
IP on the screen :)

require 'net/http'

Net::HTTP.get_response(URI.parse('http://www.wieistmeineip.de')).body.scan(/^Ihre 
IP-Adresse ist.+/) { |ipadresse| puts 
ipadresse.sub(/^.+">/,'').sub(/<.+$/,'') }

greets