The leap motion supports the recognision of gestures, it seems to support 4 types of gestures out of the box:
CircleGesture A circular movement by a finger.
SwipeGesture A straight line movement by the hand with fingers extended.
ScreenTapGesture A forward tapping movement by a finger.
KeyTapGesture A downward tapping movement by a finger.
So we could possibly create an inworld book/presenter, wich could be controlled with gestures, to go trough the slides with SwipeGestures.
A CircleGesture could be used to call up a UI with possible a with a leap keyboard and some sort of menu.