powermated is a program for controlling X applications and command line programs, and for monitoring various aspects of your computer with the Griffin PowerMate USB dial. It can update the PowerMate's LED based on different system monitors (such as CPU usage, XMMS/BMP sound output, and system mixer volume). It also has XOSD support for nifty on screen status displays.
Recording level monitor records analog audio from the sources you choose and plays it back simultaneously so that you can hear it, while monitoring the loudness (input) level of the recording. You'll be able to hear and see whether the volume is too high (introducing analog distortion and digital clipping) or too low (letting through background noise and hiss) on your audio gear.
GSmartMix provides a smart control of the audio on GNOME. There is also an applet which allows manual adjustment of sound per application. Each application using GStreamer can benefit from this project without any intrusive patch. Other applications should implement the D-Bus interface proposed with GSmartMix to be seen by the smart manager.