Asynchronous DNS Resolver for Haskell is a library that provides an asynchronous DNS resolver on top of GNU ADNS. Not all options are supported, but A, MX, and PTR lookups work nicely. There is also support for retrieving generic RR types, CNAMEs, and for NSEC zone walking. The library can be expected to work with fine ADNS 1.4 or later. It might also work with version ADNS 1.3, but that hasn’t been tested.
Postmaster is an Internet mail transport agent (MTA) that handles incoming ESMTP network connections and delivers accepted messages to the user's mailbox by piping it into an arbitrary local mailer (such as Procmail). It is configurable beyond anything you'll ever need, handles any number of concurrent connections without forking or using OS threading, and it is pretty efficient. It currently lacks any form of queue management, but for leaf sites that don't need to do extensive mail relaying, it is a reliable and powerful solution.
Wikipedia4epub is a set of commands that constructs an offline e-book from articles on Wikipedia in EPUB format. There are commands to create an EPUB book from the articles from Firefox history file, or create an EPUB book from the given article and its children. It is useful for people with offline e-book readers.
log2rotate is designed for rotating backups with an optimal balance between retention and space usage. Instead of rotating backups using some fixed period such as daily, weekly, monthly, or yearly, it rotates backups using exponentially-growing periods. The exponential periods are based on the base 2 logarithm or squaring, depending on how you look at it.
Himerge is a GUI for emerge (Gentoo's Portage system) written in Haskell using gtk2hs. The main idea is to simplify browsing the entire portage tree, and allow running the most basic and common options from the emerge command. It also offers several handy tools, like global and local use flags browsers, inspired by UFED (the Gentoo Linux USE flags editor). It also uses eix (a small utility for searching ebuilds with indexing for fast results) as a back-end command to show package information in HTML/CSS format, so you can access a package's Web site for a quick glance.
HDBC provides an abstraction layer between Haskell programs and SQL relational databases. This lets you write database code once, in Haskell, and have it work with any number of backend SQL databases (MySQL, Oracle, PostgreSQL, ODBC-compliant databases, etc.) HDBC is modeled loosely on Perl's DBI interface, though it has also been influenced by Python's DB-API v2, JDBC in Java, and HSQL in Haskell.