I think Holograms are the next big thing.
This example of a hologram on an an iPhone App is pretty amazing as an early version of what is to come.
Just wait for hologram phone calls and meetings and integration with everything social media.
I see things like avatars--graphical representations of users-- as a precursor to actual 3-D projected images of ourselves that will be sitting in the classroom, going to the office, and even interacting socially like going on dates with our favorite other.
This is going to make things like Skype, Facetime, and Telepresence just baby steps in our ability to project ourselves across space and time and "be there" in ever more realistic ways participating and interacting with others.
As part of a training class a number of year ago already, I had the opportunity to see a spatial hologram that was very cool. So holograms are not limited to only people but entire environments that can be virtualized and this gives us the opportunity to test new ways of behaving and model and simulate new worlds.
This iPhone App is just a teaser of what is coming.