Even if the original Nintendo Entertainment System was well before your time, you're probably still aware of a well-known issue that prevented games from working until you blew into the cartridges to clean off the contacts. Taking that idea one step further, YouTuber Basami Sentaku has turned a few old NES (or Famicom, to be exact) cartridges into electronic harmonicas that instead produce chiptune-like music when you blow into them.
A series of microphones are arranged in a row where the cartridge's metallic contacts used to be, detecting where the player is blowing and producing notes or sound effects accordingly. Had Nintendo built similar functionality into its NES and Famicom cartridges back in the day, blowing into carts might have been more fun than the actual games. [YouTube via Cnet]