The Vectrex

Vectrex with controller - from here

Background/History:
By 1982, the home video game market - led by the Atari 2600 - had become huge, but the crop of consoles on the market had become dated. Arcades were getting games with more and more impressive technical specs and innovations, and the home consoles found themselves unable to keep up with them. In 1982, a new generation of consoles arrived, promising to bring an up to date arcade experience home. This generation was led by three consoles - the ColecoVision, Atari 5200, and the GCE Vectrex.
While the ColecoVision and 5200 were both traditional game consoles made by established game companies, this was GCE's first venture - and used a different design from any other video game console. Other video game consoles used raster graphics, which involve rendering the picture as pixels. The Vectrex used vector graphics, an innovation used by several popular arcade games of the time. Vector graphics use lines and shapes instead of pixels, and allowed for smoother animation than any other console of the time.
In addition, the Vectrex included its own screen, and didn't require - or even allow - a television to hook up to. One could simply plug the console in and play. The console featured a nine inch screen. It weighed over 10 pounds, so it wasn't a portable - but it wasn't quite a traditional console, either.
The Vectrex had two peripherals that were also never before seen: a 3D imager (much like movie 3D glasses), and a light pen that allowed the player to draw on the screen display.
Over 80 games were released on the Vectrex.

What Makes It Obscure?
The Vectrex was released in November 1982, immediately before the video game crash of 1983-1984, and was produced for only a year. While the Vectrex was well received and sold well at introduction (well enough for Milton Bradley to buy out GCE), it wasn't able to match the success of the ColecoVision and 5200.
The system has maintained a small, devoted fan base, whom have released home brew games. The system has also been praised for its durability, controller design, and game library.