Magicard

This is one of the most sought after Atari 2600 games ever made. The game was only available via mail order from CommaVid. It had no box, but did come with a 100 page manual.

This cartridge is not actually a game. It is an entire Atari 2600 programming system on a cartridge. This could be used to make your own Atari 2600 games. It had its own programming language, explained in the lengthy manual, and used the Atari Keypad as a controller.

This programming cartridge is very hard to use, so don't think you will be making your own games that easily. However if you get one it will be the shining star of your Atari collection. It is extremely valuable due to its uniqueness. Expect to pay over $800 for a copy of this game. You will pay quite a bit more if the 100 page manual is included.