Wakaba and Kareha are my attempts at implementing from scratch image and message boards of a type popular in Japan (used on sites such as Futaba Channel and 2channel). This kind of board software is built around anonymous posting and no requirements for registration, to make the boards more suited for casual uses, and more fun overall. They are written in Perl, and are designed to be more efficient and cleanly written than the original scripts that are available, while preserving the same kind of functionality. Both scripts are in use at iichan, an English-language site built along the same lines as the Japanese Futaba Channel, and also 4-ch, an English-language discussion BBS.
This is a script that allows you to put postit-like notes on images, and editing them. The editing uses a wiki-like model. It is written in Perl, and uses an SQL database to store the notes.
Currently, I have an installation running, which is mostly used for translating comics. The uses for this is probably not limited to just that, so feel free to download it and use it for your own purposes!
It is not a very mature piece of software yet, and it has numerous bugs and issues with bugs in browsers, but it works, after a fashion. Any outside contributions to the development of this would be warmly welcome, as I don't currently have much time to work on it.
In addition to the regular download, it also features a Perl self-installer, which you can just upload to your site and run as a CGI script.
More information is available in the discussion thread.