My forum software written in Perl in 2001.
The free external embeddable forum service I was using on one of my projects (SaaS before SaaS was a thing) was suddenly discontinued. Faced with the need to find a new solution to continue discussions on the website, I decided to develop my own forum engine in Perl instead of switching to another unreliable service. I replicated the look and feel of the discontinued forum, using a completely different programming language.
I didn't know Perl, I didn't know databases, and I had to write this real quick.
So please don't judge! :)
Open-source forum engines like phpBB, Phorum, SMF, and bbPress for WordPress were getting better and better with each year, so I ultimately retired my script after using it for a couple of years and switched to open source.