I have a little calendar and events display that started out as an ISPF application written in PL/I back in the mid 1980s. Later I rewrote it in C, and made it generate HTML as a CGI app. Later on, it was ported to Perl, and oddly, also forked into a C++ program. For each version, what started out as a "word-for-word" translation was refactored and reworked to match the features and idioms of the new language. However, I haven't gotten around to making it "use strict" yet. Once I do, maybe I'll submit it for a scathing review in the monastery. :-)

It has indeed been very useful for learning new languages for me... I can start with what's common with a language I already know, and incrementally add features and techniques as I learn them. And it lets me concentrate on the language, instead of solving a new problem. Which would be the next step.

Here's a site that shows it working: http://sas-crash.homelinux.net/sas/cgi-bin/logon9c.pl. Bug reports are welcome.

Update: fixed the link.. I swear it was good when I put it in.