A Liquid Crystal Display (LCD) allow your Arduino to display some text. You might want to show a reading such as the current temperature. In the hacklab we use one to show the total time the laser cutter has been running.
The LCD included in your kit has 2 rows each with 16 characters and has a backlight to make it easier to read. It uses a Hitachi HD44780 compatible driver chip well supported by Arduino software libraries.
(1) Using the examples from the tutorial scroll a message that is longer than 16 characters across the display.
(2) Connect up a push switch to the Arduino and display “Switch On” when the button is pressed and “Switch Off” when the button is not pressed.
(3) Display an arrow pointing to the right (→) on the screen.
(4) Scroll the arrow pointing to the right (→) across the screen. As demonstrated in this video.
We'll use the LCD in later tutorials. It is amazing how much more professional a project can look with an LCD!