Guake is a drop-down terminal for GNOME and any other desktop. It aims to provide a quick-access terminal, that show/hide on screen with a simple key pressing. Its style of window is based on an fps games, and one of its goals is be easy to reach.
Guake is written mostly in python and has a little piece in C (global hotkeys stuff).

Installing Guake

The latest version of Guake 0.4.4 is available in the default repository of Ubuntu. To install Guake open terminal and run following command:

# sudo apt-get install guake -y
About guake screen

About guake screen

After the installation is complete, click on ‘Menu > Accessories > Guake Terminal’ to launch the application.

Start Guake Terminal

Start Guake Terminal

An icon will appear in the system tray.

Guake system tray icon

Guake system tray icon

Press the hotkey ‘F12′ to show/hide Guake terminal.

Guake terminal

Guake terminal

If you want Guake available every time you log in, you should add it as a startup application. To do that, open the Control Center and then startup applications in Linux Mint or in Ubuntu go to System > Preferences >Startup Applications, and add  Guake as a startup application.

And add Guake as a startup application

And add Guake as a startup application

That is all.