One more suggestion in regard to creating user interfaces:
Robert Penner's easing functions:
http://www.robertpenner.com/easing/allow you to create the effects that give objects a feeling of mechanistic weight on the screen and "snap back" effects. Many developers when they use roScreen to implement a UI leave out smooth motion, and everything just jumps in a stiff way when you move from one point item to another, as opposed to the kind of smooth slide you see in the roGridScreen (netflix, amazon etc).
- Joel