Just as the title says, this glitch allows you to play any item as the ocarina.

Glitch: Get a bottle full of a bug or fish, and let the item out. Put the item back in again and Link will be holding the bottle in his hand. Jump off of a ledge and while in the air, press the bottle button and either a C button item or the sword button right after. Link will be holding the item to his mouth which you can play like the ocarina.