Here's a list of some free / open source software I have written over the years. Enjoy!
A C++ library that generates invertible constant-Q spectrograms. See the Gaborator home page.
The Gaborator forms the basis of Spectrolite, a real-time constant-Q spectrogram app for iOS.
A simple tool for generating printable call graphs of C programs. See the egypt home page.
A 96 kilobit/s DSL softmodem for BSD/Linux systems, using PC sound cards as the line interface. See the AuDSL home page.
A network Mandelbrot program. See the MandelSpawn home page.
This obfuscated anagram program won the award for "most humourous output" in the 1992 International Obfuscated C Code Contest. It's not only highly obscure C code, it's also one of the fastest anagram programs on the planet. It is available by HTTP from this server as two separate files: the source code file gson.c (all 1513 bytes of it) and the documentation file file gson.hint.
AG is now also available as an iOS app.
An interpreter for the CHIP-8 video game virtual machine language running on the HP48SX pocket calculator. The original CHIP-48 distribution is available by FTP in ftp.funet.fi:/pub/misc/hp48sx/chip/chip48-2.25-bin. The same directory also contains an enhanced CHIP interpreter called SCHIP and other related software.