Note: see also my projects on GitHub, BitBucket.

I'm using all software listed below right now, so it's fairly stable. But it tested only on Linux (and some designed to work only on Linux).

Script which add GnuPG info into email headers while delivering (for use in .qmail). This is useful if you automatically decrypt PGP-encrypted/signed messages, and so you didn't see is that message was encrypted/signed or not in your MUA. With that script you can check "GPG:" email headers in your MUA to see is that email was encrypted and correctly signed.
Trivial script which analyse directory structure on your Kindle and generate collections with same names as directories (with subdirectories).
Personal OpenID server
Very simple OpenID server for paranoid people who bother about their privacy and don't trust public OpenID service providers.
You'll need CPAN module Net::OpenID::Server to use it.
Also very good as simple starting point for developing your own OpenID server in Perl.
I wrote small article about it.
View your AsciiDoc-formatted documentation in browser.
This script will automatically convert your *.txt files into *.html on-the-fly when user send request to your website, so you can just update *.txt file and immediately view changes on website.
About documentation system
tcpserver-compatible anti-spam (greylisting) smtpd.
Input Event
Allow you to configure keyboards with additional (multimedia) keys.
Simple and flexible incremental backup.
Ease to use wrapper tools for ssh and scp.
Control email delivery (for .qmail only).
Search dictionary located in MySQL database.
Library for fake access to files from external app.
A bundle of useful small utilities.