This is Chumby Suite project - QT/C++ GUI and framework for chumby suite.
You'll need crosscompiler and chumby toolchain (as well as QT) set up to compile this project for device.
You can find detailed instructions here: http://forum.chumby.com/viewtopic.php?id=5974.
You can run it as windows application as well, chumby rotary button and hardware button will be simulated:
shift - hardware button,
ins,del,PageUp, PageDown - rotary.

Double click on hardware button brings up widgets menu.