A few of the more accessible program I have written are available below. They're all Java programs zipped up for faster downloading. Unzipping the ZIP file and running the JAR file should run the program.
The ZIP file can be unzipped by double-clicking it or by typing
unzip ZIPFILENAME
on the command line.
The JAR file can be run by double-clicking it or by typing
java -jar JARFILENAME
on the command line.
The lib directory contains all the additional required libraries and should be kept in the same directory as the JAR file (otherwise you'll get an error saying classes cannot be found). Java 5 or higher is needed to run any of these programs.
All this software is still in active development and I am not responsible for any harm it may do to your computer or data. Thankfully the JVM should make the chances of any harm occuring fairly slim.
A non-exhaustive list of people I've worked with.