DeforaOS Mixer is a graphical volume mixer written in Gtk+. While initially written for NetBSD's own audio API, it also supports OSS (which is used on systems such as *BSD and Linux).
FB-Mix is designed to sit in the Fluxbox system tray and popup an alsamixer window when clicked. It should also work with other window managers. As of version 0.2, volume can also be adjusted using the mouse scrollwheel when hovering over the icon.
An application to annotate screenshots.
An implementation of LoLCode.