Bit::Vector is a (stand-alone) C library and an object-oriented Perl module (with overloaded operators) which allows you to handle bit vectors, sets (of integers), "big integer arithmetic" (e.g. for cryptography), and boolean matrices (all of arbitrary size) very efficiently.

The Date::Calc package consists of a (pure-Perl) wrapper which either loads Date::Calc::XS (a separate implementation in C and XS) or Date::Calc::PP (a pure-Perl implementation which is part of the Date::Calc package). The Date::Calc::XS and Date::Calc::PP modules perform all kinds of date calculations based on the Gregorian calendar (the one used in all Western countries today), according to relevant norms and standards: ISO/R 2015-1971, DIN 1355 and, to some extent, ISO 8601 (where applicable). The package is designed as an efficient toolbox, not a bulky ready-made application. It provides extensive documentation and examples of use, multi-language support, and special functions for business needs.

The Date::Pcalc Perl module is a direct translation of Steffen Beyer's excellent Date::Calc module from a combination of C and Perl to Perl only. The Perl module does all kinds of date calculations based on the Gregorian calendar (the one used in all western countries today), thereby complying with all relevant norms and standards: ISO/R 2015-1971, DIN 1355 and, to some extent, ISO 8601 (where applicable).

The number perl script will print the English name of a number. One can print names of extremely large numbers (e.g. 1e1234567). Number can be run on the command line, or as a CGI script when run as 'number.cgi'. Number prints names in both the American and European naming system. It can also print the decimal expansion of a number in either naming system.

Elca (Extended Line Calculator) is a real-time Perl calculator (i.e., it evaluates expressions immediately as you type them). It supports hexadecimal, octal, and binary numbers, complex numbers, variables, string, list and hash operations, etc. It can convert expressions from human style to valid Perl code before evaluating them, and has a mechanism for importing external modules, allowing almost arbitrary extensions.

Condorcet with Dual Dropping is a ranking system for deciding single or multi-winner contests (elections) using voted preference (or approval) ballot list or pairwise tally matrix. It computes the Cloneproof Schwartz Sequential Dropping (CSSD) and Tideman's Ranked Pair (RP) results for each contest round, and selects the combined CSSD and RP outcome with the lowest overall dropping cost. There are options to compute just the CSSD, RP, or Minimum Dropping Cost outcome, various optional pair rank and winner tie-breakers, and alternative measures of dropping cost (winning votes and/or margin). It comes as a console program and CGI executable.

The Chombo package provides a set of tools for implementing finite difference methods for the solution of partial differential equations on block-structured adaptively refined rectangular grids. Both elliptic and time-dependent modules are included. Support for parallel platforms and standardized self-describing file formats are included.

GLgraph is an interactive OpenGL based function grapher for Linux written in Perl. It visualizes any mathematical function in 1, 2, or 3 unkowns (x,z,t) in a 2D, 3D, or 4D wireframe or solid surface. It creates an animation after one time period. GLgraph has a command line interface to input a function, to specify the minimum and maximum plotting bound, and more. It can be interactively controlled with the keyboard.