Bandai had a penchant for making strange hardware for the Family Computer that only accepted its own special cartridges and did its own special things. Bandai's Karaoke Studio lets you sing via your FC; the Datach Joint ROM System, released in late 1992, lets you play specially-made barcode compatible games.
The unit itself sits on top of the Famicom and has a barcode reader and a slot for its own games. The games, like the Karaoke Studio carts, are incompatible with the FC without the Datach unit. The carts are really small; about half the length of regular FC carts making them almost cubic in size and comparable to Game Boy carts.
The Datach, attached to an AV Famicom. Datach carts are inserted into the rear
of the unit and barcode cards are run through the scanner on the top
(near the yellow arrow).
View the box
Crayon Shin-chan is a really badly animated cartoon show in Japan, featuring tons of somewhat juvenile bathroom humor. (thus satisfying my two requirements for quality television viewing) Strangely enough this game doesn't use the Datach's barcode feature at all. It's a Tetris-inspired game with two players throwing cards at each other and making matches... the object being to create a stack that breaks into the opposing player's field.
View the box
View some of the barcode cards
The J.League is a Japanese professional major soccer league. This game comes with cards that represent four players in each team of the league (some of the teams have since folded, by the way), and the game plays out in a sort of strategy, Tecmo Cup Soccer-style game.