beep does what you'd expect: it beeps. But unlike printf("\a"), beep allows you to control pitch, duration, and repetitions. Its job is to live inside shell/perl scripts and allow more granularity than one has otherwise. It is controlled completely through command line options. It's not supposed to be complex, and it isn't - but it makes system monitoring (or whatever else it gets hacked onto) that much more informative.
CDDBD.sh is a shellscript speaking the CDDB Protocol version 1 without enhancements and read only. CDDBD.sh allows to query a local database on a filesystem that was filled with entries using such programs like xmcd or kscd. CDDBD.sh was developed to be used in a local or home network and not to serve a WAN.
ctrlxmms is a small Perl script designed to increase the useability of XMMS. With it, you can use most of the common GUI functions of XMMS from the CLI. You also have a few handy commands which are not available from the GUI. Together with lirc and a remote (eg. Anir Multimedia Magic), this is a wonderful tool.
dmcat is a Digital Music CATalog program. Written in Perl, it recurses a physical directory, searching for digital music files, and builds a virtual catalog (out of symbolic links) in a sister directory. It currently only supports the MP3 format using ID3 tags. The following hierarchies are supported: Album, Artist, Artist_Album, Genre, Miscellaneous (catch-all), Title, and Year.
napMan is an infobot that provides you with a real time glimpse into the current state of the worldwide network of nap servers that are based on either the closed source Napster protocol or the Open Source opennap protocol. It displays a list of all the nap servers and current statistics for each server (users, number of MP3 files, gigabytes), and provides the ability to ping individual servers and check the network lag time, a facility to save the list of servers and statistics to a file, and the ability to refresh statistics for individual servers or all the servers.