AngeTheGreat's Engine Simulator: Procedurally Generating Audio Using a Real-time Fluid Simulation (Technical Breakdown)
This screwed over a few projects which are unable to re-license to an apache2-compatible license. Offhand, I believe it affected the LGPLV2.1 licensed Wine/Codeweavers win32 emulation layer for running windows 32-bit programs on a 64-bit-only mac, and affected several other programs as well.
I took a shot at making a modernized port of speak.c myself not long after the code was found, but it didn't get very far, sadly. I couldn't figure out an easy way of dealing with the multiple-character character constants.