The Legend of Zelda: Ocarina of Time 3D Glitches

Play Ocarina of Time Before You Actually Get It
Note that doing this makes it impossible to complete the game, so make sure you don't actually save after doing this.

Play the game up to the point where you will be taught a song where you still have the fairy ocarina (eg Zelda's Lullaby or Saria's Song). Now go grab a bottle (either at Kakariko or Lon Lon Ranch after waking Talon). Perform the duplicate bottles glitch and use it to replace your ocarina with a bottle. Now whenever you go to learn a song Link will pull out the ocarina of time despite not actually having it yet.