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).
acoc is a regular-expression based colour formatter for programs that display output on the command-line. It works as a wrapper around the target program, executing it and capturing the stdout stream. Optionally, stderr can be redirected to stdout, so that it, too, can be manipulated. acoc then applies matching rules to patterns in the output and applies colours to those matches.
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.
RFind indexes the filenames of a given directory, and allows you to quickly search this index with regular expressions. Search-on-typing with more than 500,000 indexed filenames is easily possible. This tool attempts to be very configurable so that it can be useful to everyone. It features hierarchically presented search results, search-on-typing, and the ability to define rules to execute on mouse click.