Search::Xapian is a Perl XS frontend to the Xapian C++ search library. It is a fairly complete wrapper: most features of the Xapian library are made available for use from Perl. Xapian is a highly adaptable toolkit that allows developers to easily add advanced indexing and search facilities to their own applications. It supports the Probabilistic Information Retrieval model as well as a rich set of boolean query operators. It's fast and scalable to hundreds of millions of documents.
Zoidberg (a.k.a. zoid) provides a modular Perl shell written, configured, and operated entirely in Perl. It aspires to be a fully operational login shell with all the features one normally expects. But it also gives direct access to Perl objects and data structures from the command line, and allows you to run Perl code within the scope of your command line.
Sprog is a graphical tool that anyone can use to build programs by plugging parts together. In Sprog jargon, the parts are known as 'gears' and they are assembled to make a 'machine'. Gears are selected from a palette and dragged onto the Sprog workbench, where they can be connected together. Options can be set using a properties dialog on each gear. When assembly is complete, the machine can be run, reconfigured, or re-run.
ComicMan downloads Web comics from the Internet to your hard drive. It remembers the last download for each title, so you won't get duplicates from running it multiple times. The application itself is a command line tool, but it comes with a graphical configuration tool and an editor for making new Web comic configuration files.
Huntor is a full-featured command line Bittorrent client. It currently has no GUI. This client focuses on being run in the background, such as on servers. It is highly customizable. Its disk storage layout makes it easy to incrementally rsync the data to a different machine while downloading.
Webupdate is a script which lets you register Web pages and monitor them for updates. An email alert is sent to your local account whenever an update is found. It is also possible to register a pipe of commands to filter which content on the Web page should actually trigger an alert. The script can be used with crontab to get regular notifications whenever registered Web pages are updated.