8-bit Harmonica - Blow into the cartridge for music
This harmonica not only has a Famicon cartridge case, it also produces 8-bit sound when you blow into the cartridge! The 8-bit sound in this harmonica is achieved using a set of pipes that you blow into that are programmed to reproduce the chiptune sounds as heard in the original Super Mario Bros. Multiple modes allow you to switch between playing music or the coin sound effect from the game. Whether you're a video game fan or not, this is definitely a cool idea!
Source: Basami Sentaku via YouTube