Yakuake (Yet Another Kuake) is a KDE terminal emulator.  Its design was 
inspired from consoles in computer games such as 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.

Running Yakuake 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.
