Current Stuff
MASON MASON is a free, open-source discrete-event simulation toolkit written in Java. MASON is designed for single-process “swarm”-style multiagent simulations.
ECJ ECJ is a free, open-source evolutionary computation research library written in Java. ECJ is designed to support large, complex projects.
FlockBots An open design for differential drive robots based around a Gumstix controller. The FlockBots sport bump sensors, dual odometers, five range sensors, a tilt-servoed camera, a gripper, I2C extensions, and wireless networking. Nowadays we use the same platform to support humanoid robots too.
The Mersenne Twister in Java The Mersenne Twister is an exceptionally high-quality, fast random number generator. I have coded two versions of it in Java. MersenneTwister.java is a complete drop-in subclass replacement for java.util.Random. MersenneTwisterFast.java is algorithmically identical, except that it isn't synchronized, and it's not a subclass of Random. This, plus other speed improvements, makes it over twice the speed. Java documentation is available.
Snarf A small, lightweight prototype-style OOP library for Common Lisp. If you like the OO style of Javascript, NewtonScript, or Self, you may prefer this over CLOS. Snarf implements proto-style OO with lists and hashtables, so it's isn't super fast, but it's simple and easy to use. Snarf Version 3.1. (or the older Snarf version 2).
Older Stuff
SHOE A superset of HTML/XHTML designed to allow agents to embed knowledge representation statements into HTML. SHOE was developed at the same time as RDF, but is more sophisticated than by quite a bit. Research in SHOE was a precursor to DARPA's DAML effort.
lil-GP Tweaks A heavily patched version of the (now fairly old) lil-gp genetic programming kernel. The patch adds strongly typed genetic programming, multithreading, and various other stuff. At this point, rather than my patch, I suggest using ECJ.
Caenorhabditis elegans Embryo and Neural Visualization Caenorhabditis elegans is a near-microscopic worm whose entire neural structure, cellular organization, genome, cell ancestry, and embryonic development has been mapped out. Long ago I developed a simplistic visualization tool of the embryonic development and neural data for the worm. This tool has since been migrated to MASON.
Parka A semantic network knowledge-representation system developed at the University of Maryland. I was involved with the early development and of Parka and various projects using Parka machinery.