Okay, go to your script editor, and then find "Scene_Title".
Find lines 39 and 40 which should have this:
s3 = "Exit"
@command_window = Window_Command.new(192, [s1, s2, s3])
Replace it with this:
s3 = "Jukebox"
s4 = "Exit"
@command_window = Window_Command.new(192, [s1, s2, s3, s4])
or replace "Jukebox" with "Music Box" or whatever you ultimately decide to call it.
Now scroll down to about line 100 and find this:
when 0 # ??????
command_new_game
when 1 # ???????
command_continue
when 2 # ???????
command_shutdown
And replace it with this:
when 0 # ??????
command_new_game
when 1 # ???????
command_continue
when 2 #Jukebox
command_new_game
$game_switches[1] = true
when 3 # ???????
command_shutdown
NOTE: If you're using Switch #0001 already, simply change the "1" to a switch number that isn't in use.
When you're done you'll have a "Jukebox" option on the title screen, which will start a new game with Switch #0001 (or whatever you chose it to be) activated.
This is where the real work begins.
You need is to make sure your game starts with no hero graphic on a blank map with a single event.
(you'll also need a second blank map that I'll get to in a minute - may as well create a new one now)
You want your event to be on parallel process (or auto-start if you prefer).
Make a conditional branch to check if your switch (see above) is OFF.
If it's off, simply teleport the player to the starting position of the game and restore their character's graphic (if your game starts with one).
If it's on, teleport the player to the new map I'm about to tell you how to make.
This new map will be your Jukebox menu.
It's going to allow your player to listen to the music in the game, which is awesome by the way.
You'll need to make a tileset for this menu as well.
It simply needs to include 2 transparent tiles (one that will be walkable, and one that will not), and all the names and/or numbers of the songs in your game.
All you have to do is make a column of walkable tiles (as many as there are songs in the game), and surround it with unwalkable tiles,
then make an event for each song on each tile that plays the song when activated.
There you have it!
A Jukebox system!
NOTE: I'm sure there are others out there who could script an actual menu for you (like the item or skill menu is), but I'm not quite that good at scripting.