> Is webcal.cgi truly a CGI script?

It is -- one of the free offerings from eXtropia/Selena Sol. http://www.extropia.com/applications/webcal_perl.html

As far as I can tell webcal.cgi is not using CGI.pm. Extropia have a whole Charlie Foxtrot, I mean, um, suite of their own event-handling modules that has been developed over 8-9 years, so the level of abstraction is pretty high.