RBTray runs in the background and allows the user to minimize most windows to the system tray by right clicking the window's minimize button. It is tiny and self contained. It supports XP, Vista and Win7. Both 32 and 64 bit versions are available.
License - GNU GPL
RBTray is mentioned in one other post on this forum but very little information is provided, so I believe it is permissible for me to post this.