Nintendo 3DS:

Released globally in North America on March 27, 2011 for $249.99

Backwards compatible with Nintendo DS cartridges

(I would not be surprised if this is the only console ever to have a built in 3D feature.)

The Nintendo 3DS was the second (and last) iteration of the DS. As of April 2024, Nintendo has ceased support for the 3DS servers, leading to the loss of online play - however, local play and Streetpass are not affected, since those features work independent of Nintendo's servers. Pretendo Network, a very ambitious 3DS server project has appeared recently, and while (as of early April 2024) they aren't avaliable for public use yet, they seem to be making a lot of progress with their custom servers. If you are interested in learning more about the Pretendo Network, check out their official website. In case you were wondering, yes, this service does require CFW (Custom Firmware). A wonderful guide for installing CFW on your 3DS is located at 3ds.hacks.guide, and I can't recommend this guide enough. Unlike video guides that can get out of date really fast, this guide is constantly updated to reflect any changes or updates that happen to the official firmware. If you're interested in Pretendo, or even just custom themes and badges, give 3ds.hacks a try! I promise you won't regret it. :)