textclock.pl is a script that displays the current date and time like this:
Wednesday July 31 2007 10:27:35 EDT
To set it up on your Web site, use the script as a Server Side Include (SSI). Simply include this code in your HTML:
<!--#exec cgi="/cgi-sys/textclock.pl" -->
Make sure you change your HTML file's extension to .shtml, instead of .html. For more information on SSI, please read this article.