This script uses nokogiri to scrape a dd-wrt router front page for the external/WAN IP. It then outputs a timestamp and the IP address to STDOUT. Included with the script is a shell script for use with chron. The script uses ssh to run a remote cat command and cat the output of the ruby script to an HTML file on a remote web server. The two scripts together should allows one to find out what their external IP is without using a service like DynDNS.
install the nokogiri gem.
Simply put both scripts in your users bin direcotry and correctly set the permissions.