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.
Catalyst is a Web application framework for Perl. It is based on Maypole, and adds many features from Ruby on Rails, Struts, Spring, and Tomcat. The development philosophy focuses on Don't Repeat Yourself, Lego-like components, Code Generation, and very strong testability. It supports a number of plugins, models, views, and controllers.
Date::Manip is a Perl module for handling Gregorian dates. Operations such as comparing two times, calculating a time a given amount of time from another, or parsing international times are all easily done. The library is oriented towards the type of operations people tend to think of rather than those operations used routinely by computers.
The DBI module enables your Perl applications to access multiple database types transparently. You can connect to MySQL, MSSQL, Oracle, Informix, Sybase, ODBC, and other database systems without having to know the different underlying interfaces of each. The API defined by DBI will work on all these database types and many more. You can connect to multiple databases of different types at the same time and easily move data between them.