cppcam is a 3D CAD app for drafting G-Code toolpaths for CNC Routers
AVR simulator IDE
CNC PAD, is a CNC program with syntax highlighting editor
3D CAM program for CNC mills/lathes
Set of tools that help CNC machinists
Python Module to generate g-code
qnutCNC is a program to control the ethernut development board
Android app to control the Red CNC 3D routing machine