The ps vita has a neat feature that lets it remote into a ps3 or ps4 and allow you to play games on the ps3/4 using the vita as both screen and controller. I wonder if that's just a thin client, or if the vita does any processing on its end of things.
It's kind of a shame that neither the ps3 nor the vita can do ps2 games, because otherwise it'd be possible to play the entire playstation library from ps1 to ps4, including the psp and vita, on the vita.