When I'm not earning a living doing programming I like to make and record music and computers have played quite a large part in this for a while, being able to stand in for quite a large amount of the bulky and expensive equipment that might have been used before. LADSPA (Linux Audio Developer's Simple Plugin API) is a key platform in the increasingly usability of free and open source audio applications, allowing the creation of modular software synthesizers ( such as Alsa Modular Synthesizer) and flexible application of effects to audio tracks in digital audio workstation software (such as Ardour).
This great set of modules brings the power and flexibility of the LADSPA architecture to my favourite programming language, making it easy to create and manipulate sounds in Perl programs, building on the many excellent and interesting plugins available. Previously Perl had largely been limited to sequencing or generating notes for other software to generate the sounds, but now it can all be done in Perl (albeit with plugins written in C).
You can find a link to a piece generated with the help of this module which I presented at LPW 2007 on my use.perl journal.