This is going to tell you how to make it play different music and change the System graphic randomly when you go into your menu. First go into the database and into common events. Name one menu random and set it to parallel process and no appearance condition switch. Now your going to need a variable called menu random. The first thing you do is set a disable menu then under it make an enter password/Key input processing (it depends on which RM maker your using). Make sure everything is unticked all but "cancel" and set it to any variable, which we'll call "Key Press" in this example. Next do memorize BGM.

<>Disable System Menu: Disable
<>Enter Password: (Key Press)
<>Memorize BGM
<>

After you get that make a change variable "menu random" set random 1-5

<>Disable System Menu: Disable
<>Enter Password: (Key Press)
<>Memorize BGM
<>Variable Ch[0001:menu random] set, Rndm [1*5]


Now were going to need fork conditions make the first one set to when variable menu random is set to 1 same with no else case. Do this five more times but instead of putting 1 the next should be 2 and so on like this.

<>Fork Optn: Varb[0001:menu random]-1
<>
END CASE
<>Fork Optn: Varb[0001:menu random]-2
<>
END CASE
<>Fork Optn: Varb[0001:menu random]-3
<>
END CASE
<>Fork Optn: Varb[0001:menu random]-4
<>
END CASE
<>Fork Optn: Varb[0001:menu random]-5
<>
END CASE

After you get all that we are going to make things change (exciting, I know)!
Under the first fork option you need to put change system graphic to whatever you want, then put play BGM to whatever music you want and finally put call system menu it should look like this..

<>Fork Optn: Varb[0001:menu random]-1
<>Change System Graphic: (Whatever You want)
<>Play BGM: (Whatever You want)
<>Call System Menu
END CASE
<>Fork Optn: Varb[0001:menu random]-2
<>
END CASE
<>Fork Optn: Varb[0001:menu random]-3
<>
END CASE
<>Fork Optn: Varb[0001:menu random]-4
<>
END CASE
<>Fork Optn: Varb[0001:menu random]-5
<>
END CASE

Now do that under each one but don't put the same system graphic and BGM as the first on make them all different. Now when your done with that at the end of everything put change system graphic (to your original one) and play memorized BGM. The whole code should look like this...

<>Disable System Menu: Disable
<>Enter Password: (Key Press)
<>Memorize BGM
<>Variable Ch[0001:menu random] set, Rndm [1*5]
<>Fork Optn: Varb[0001:menu random]-1
  <>Change System Graphic: (System1)
  <>Play BGM: (Menu Music 1)
  <>Call System Menu
  <>
END CASE
<>Fork Optn: Varb[0001:menu random]-2
  <>Change System Graphic: (System2)
  <>Play BGM: (Menu Music 2)
  <>Call System Menu
  <>
END CASE
<>Fork Optn: Varb[0001:menu random]-3
  <>Change System Graphic: (System3)
  <>Play BGM: (Menu Music 3)
  <>Call System Menu
  <>
END CASE
<>Fork Optn: Varb[0001:menu random]-4
  <>Change System Graphic: (System4)
  <>Play BGM: (Menu Music 4)
  <>Call System Menu
  <>
END CASE
<>Fork Optn: Varb[0001:menu random]-5

There, now you have a cool menu!