Dancing Furby is a game that was released by TOMY in Japan in 1999 for the gameboy color. It is similar to the game Dance Dance Revolution.
This game is unique because it can interact with physical furbies. When a song is completed, the gameboy sends an infared signal to the physical furby and makes it respond in different ways depending on how well you do in the game. It will fart if the game is beaten on easy mode, play hide and seek or yawn if the song is beaten on medium mode, and dance if it is beaten on hard mode.
These two videos are play-throughs of the game: