Visor − Quake Console for your Mac

Visor on YmirVisor is a plugin for the Terminal from the same people that brought you Quicksilver, the navigation and search tool many people swear by. Basically, you install it along with another extension, SIMBA. Though the installer puts everything in the System/Library folder, moving them to ~/Library as indicated in the instructions works fine. You can configure the terminal window displayed by Visor with special settings; note that the screenshot has a semi-transparent window, even though the standard Terminal window does not. If you elect to run a quartz animation (there are several in /Developer/Examples/Quartz Composer/ if you have XCode installed), you need to make the window semi-transparent or you won’t see the animation. The transparency controls the animation composition instead of the window composition.

Yeah, that is my desktop (Ymir is the name of my Mac Mini) in the background, including my embarassingly huge list of open windows in Opera.