Ruby-GConf allows Ruby developers to write applications that store their configuration data using GConf (1.0.x). GConf is a configuration database system written by Havoc Pennington et al, and part of the GNOME application development framework (although it can be used separately).
Alexandria is a GNOME application to help manage a book collection. It retrieves book information (including cover pictures) from several online libraries, allows you to search for a book (either by EAN/ISBN, title, authors, or keyword), can import and export data into ONIX, Tellico, and EAN/ISBN-list formats, generates Web pages from your libraries, allows marking your books as loaned, saves data using the YAML format, features an HIG-compliant user interface, shows books in different views that can be filtered or sorted, and handles book rating and notes.
SSHMenu is a GNOME panel applet that makes starting up a new terminal window with an SSH connection to a remote host just a click away. A preferences dialog allows you to add and organise hosts. Window positions and sizes can be set along with a profile for controlling text and background colours as well as font details. It also includes a version without GNOME dependencies that can be run as a small standalone window or swallowed into the panel of another window manager.
GARP (Gnome ARP) is an ARP monitoring program written on Gnome with the GTK toolkit and Ruby. It takes ARP tables and some system variables via SNMP and ARP protocols and determines whether any machines have changed their IP address. It is useful for detecting new machines on the network and detecting which machine have changed addresses. It is intended especially for network admins.