Here's a quick example I whipped up. Keyboard Controlled Menu
The basic idea behind it is you have two global variables: 'menu' and 'submenu'. Menu acts as the current selected choice, while 'submenu' determines which submenu you're on. Pressing down and up will add and subtract 1 from menu respectively. Hitting enter will, based on the value of menu, take you to a different submenu. The bottom choice will always take you to the main menu. You could ultimately string together an unlimited ammount of these submenu's, also altering the number of choices, but this is just a quick example. Hope that helps.