Within the scope of a semester class on Interface Design I developed and implemented a GUI for our strategy game project:
"Planet X - the Alliance".
The concept was to replace list menues (of distinctive single choices) with a fluent transition between two extremes.
For example: the behavior of the unit AI would not be selected from a drop down menu (stay still, patrol around, do whatever),
but controlled via the basic attitudes of that unit (aggressiveness, movability, range etc).
The design document (german only) explains more about the concept and implementation.
I implemented it into the engine of the game using C++/Direct3D.
It's fully operational and features call-back message passing.