Have ambient music playing while the system displays a game cartridge at the home menu. The cartridge will "dance" to the music that the system's microphone picks up.
Hidden Breakout game (New 3DS Models Only)
In the internet browser's new page screen, tap the touch screen six times to the tune of the first six notes of the classic Super Mario Bros. overworld theme. The text "Favorite Bookmarks" will change to "STAGE SELECT" to confirm correct entry. Now choose any site you have bookmarked to play a hidden breakout game, with the blocks arranged to form the chosen site's URL.