cgi-mailer is a simple system enabling users to have HTML form input formatted in a user-defined way and sent to an email address, without needing a new CGI program for each new HTML form or any user access to the cgi program. cgi-mailer does not need to reside on the same server as the HTML forms that use it, so you only need to install it once for your entire organisation.
cgi-mailer has featured in Perl Success Stories.