Cortana is available on Xbox One, if you know the right tricks

Cortana (in Halo, not the Xbox One)

Microsoft won't officially bring its Cortana voice assistant to the Xbox One until 2016, and it's not even supposed to be available if you're using the console's interface preview. However, that isn't stopping you from trying it ahead of schedule. Gamers have discovered that you can access Cortana in the latest preview simply by visiting the settings menu, going up and mashing the A button multiple times. It doesn't offer the full range of Xbox commands just yet, but you can access any information that's already available in Cortana on other platforms, like your calendar. Think of this as a cheat code for the operating system -- you're getting a peek at something that most preview users won't see for weeks.