Wikipedia
Guake is a drop-down terminal for GNOME Desktop Environment. Like similar terminals, it is invoked with a single key, and hidden by pressing the same key again.
Its design was inspired from consoles in computer games such as that of Quake which slide down from the top of the screen when a key is pressed, and slide back up when the key is pressed again.
Guake follows the same line of Yakuake and Tilda, but it is an attempt to meld the best of them into a single GTK-based application. Guake has been written from scratch.
Running Guake is faster than launching a new terminal with a keyboard shortcut because the program is already loaded into memory, and so can be useful to people who frequently find themselves opening and closing terminals for odd tasks.