manqod is a tool for handling any data for which you can write queries. You can design manqod to be a frontend for users to view data in lists and modify data in lists or forms. You can write events to do more than just data management. The whole frontend is built dynamically, and you design it.
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.
4Sports is an exercise management application. You can use it to analyze your exercises in a number of ways. 4Sports can import data from the Garmin "Forerunner 201/301" devices, and can display some information in a table and in a graph (like heart rate over distance). It's also possible to export the tracks (GPS data) into Google Earth, where the track is color-coded according to your heart-rate. The graphs can be exported to SVG files.
The Ruby on Rails SubList Plugin makes it easy to have dynamic lists of related models on a single editing page. The plugin is designed for models with one or more has_many relationship with other models. By using AJAX for adding and removing "sub-forms", one can present the user with a single edit page that creates/edits the parent model as well as all of the children.
rtkmerge is a GUI to the emerge command to handle packages under the Gentoo Linux Distrubution. It was initially written to help when running 'emerge world' to update the entire system. With rtkmerge you get all the outdated packages presented in a list and you can easily select which packages you want and don't want. USE-flags can be set individually for each package.
RDQS (Ruby Data Query Shell) is a text-based shell for querying SQL databases. It features connection bookmarks, shortcuts, history, completion, paging, shell interaction (via backtick operator), CSV/INI/XML/Table output, output redirection, numerous configuration options, multiconnect with fast switching, and a watch command (execute given query/shortcut in a fixed interval).