Unless otherwise noted, everything can be assumed to be licensed under the GPL.
In addition to the programs listed here, I've written many of the PHP scripts used on this site, with the notable exception of Wordpress. Let me know if you want to see the source to any of them, and I'll post them up here.
Generates sine waves based on the specified historical temperament. This is intended to be used for tuning harpsichords and other keyboard instruments. The interesting thing about this program is that the temperaments are defined in the same way that you would tune by ear - rather than entering frequencies or derivations from equal temperament in cents, you specify whether an interval is tuned pure, or tempered by a certain amount.
See the README for more information.