Comanche is a quality, cross-platform, GUI tool for configuration and management of open source software. Packages supported include the Apache Web server and Samba. It is easily extensible through plugins.
StompBoxes is a realtime audio effects processor, designed specifically for guitar, but usable by different instruments which send an electric signal. The program processes the signal at 44.1khz in 16 bit and requires a full duplex soundcard in order to work.