You won't need HoloLens or some other special headset to experience mixed reality in the classroom. Microsoft is preparing View Mixed Reality, a built-in viewer for Windows 10 that will make it easy to see virtual 3D objects (created in 3D Paint) in the real world. All you need is a PC with a webcam -- preferably rear-facing, of course. If teachers want to show you the relative size of a Mars rover, they just have to load the viewer and give you a look. View Mixed Reality will be available sometime this fall, and it can also be used on Windows Mixed Reality hardware arriving in a similar timeframe.
Check out all the news from the MicrosoftEDU event here.