The festvox project, based at Carnegie Mellon University, distributes documentation, scripts, and examples that should be sufficient for an interested person to build her own synthetic voices in currently supported languages or new languages in the University of Edinburgh's Festival Speech Synthesis System. The quality of the result depends much on the time and skill of the builder. For English, it may be possible to build a new voice in a couple of days' work; a new language may take months or years to build.
The Free Animation and Modeling Project (or FAMP), is a project to create a full-featured 3-Dimensional Modeling and Animation System. FAMP shall include support for animation, animated modeling. FAMP already includes the ability to extend easily without modifying code thanks to a plug-in architecture.
ELE is a realtime audio effect program. Effects have low latency, and are suitable for live guitar or vocals. Chaining of effects is possible, and feedbacking effect chains are allowed. ELE supports looping and synchronization of PCM WAV files, and you can even record sample loops on-the-fly.