Before E3 took place, Atari sent out this short little video that showed off a new piece of hardware with the old-school fake wood finish on the sides. They didn't really give much away beyond a link that really doesn't add anything to the hype, just a chance to sign up for updates. A lot of people on social media immediately assumed it was going to be some kind of gaming console, but also added that it would be highly unlikely considering the source. Flash-forward a few weeks later and it is confirmed that Atari is indeed making a new gaming console.
Atari CEO Fred Chesnais gave an interview to Venture Beat, in which he confirmed that the new console will be PC-based and they're currently still working on the design of the hardware. Safe money would say we're not going to be seeing anything in 2017, earliest would be PAX East or E3 2018 for this kind of reveal if they don't go the Nintendo route and do their own thing. If it's PC based but being called a game console, chances are this may be the Atari version of a Steam Machine with their own software and shop.
Atari has had an interesting history of being one of the founders of the first video game boom in the '70s, and also being one of the biggest failures two times over. The last time they attempted to do a console was in 1993 when they released the Atari Jaguar, which was an absolute flop that couldn't deliver, and relegated the company back to making arcade cabinets for a few years before becoming another developer in the modern gaming mix. If they're taking another stab at a proper console, either they think they've got a chance to corner part of the market, or they got something special up their sleeves that no one else is thinking about. Anything less is a recipe for another console failure.