The Atari 2800 was released in 1983 to attempt to break into the Japanese games market. The very similar name ought to give you a clue as to what this machine was based upon - it is, internally, exactly the same as an Atari VCS/2600. The case was a complete redesign, however, and looked quite different from anything released in the USA - that is, until Sears (who licensed the 2600 from Atari) decided to use it as the "Sears Video Arcade II". Apart from this, the 2800 was never sold outside Japan.
As well as the totally redesigned console, a number of popular 2600 games were released with it, also bearing the "2800" name. This packaging was similar to the silver-boxed releases of the early 80's. However, the actual cartridges themselves sported the original labels as the US releases - in English.
Sadly the machine did not fare as well as it had done in other parts of the world. The Nintendo Famicom was released not long after, and its success is all too well known. It was a case of too little, too late for Atari, who could not stand up to Ninty's machine.