Powerful free video editor.
AviSynth is a script-based video editor which operates on avi files. Windows Only.
Virtual Dub is an avi viewer and simple editor that is useful if using AviSynth. This is one of the three pieces of software we use to make ArtSwarm. Windows Only.
A popular sound editor.
SunVox is a modular synthsizer and sequencer, a tool for making music.
Another tool for making simple tunes, not as complicated as SunVox.