When is an extremely simple personal calendar program, aimed at the Unix geek who wants something minimalistic. It can keep track of things you need to do on particular dates. It's a very short and simple program, so you can easily tinker with it yourself. It doesn't depend on any libraries, so it's easy to install. You should be able to install it on any system where Perl is available, even if you don't have privileges for installing libraries. Its file format is a simple text file, which you can edit in your favorite editor.
mysqldiff is a Perl script which compares the data structures (i.e. table definitions) of two MySQL databases and returns the differences as a sequence of MySQL commands suitable for piping into mysql which will transform the structure of the first database to be identical to that of the second (c.f. diff and patch). Database structures can be compared whether they are files containing table definitions or existing databases, local or remote.
LaTeX::Table is a Perl module that provides functionality for an intuitive generation of LaTeX tables. It ships with some predefined, good-looking table styles. This module supports multi-page tables via the xtab and longtable LaTeX packages. For publication quality tables, it utilizes the booktabs package. It also supports the tabularx and tabulary packages for nicer fixed-width tables. Furthermore, it supports the colortbl package for colored tables optimized for presentations. The ltpretty program makes it easy to use this module from within a text editor such as Vim or emacs.