planes is a hierarchical surface framework for PyGame by Florian Berger.

The planes module introduces the "Plane" class which extends PyGame's 
"Surface" functionality, offering a hierarchy of mouse-sensitive, draggable 
Surfaces that can be used as sprites, windows, icons or other interactive 
elements.

In addition, the planes.gui module uses planes to provide basic GUI 
elements like container, label, text box, option list and button.