pyRetro is a MAME frontend written in pygame. It is easy to use and features nearly automatic configuration. It is designed to be used in an arcade machine cabinet.
Attract-Mode is a graphical front-end for command line emulators such as MAME, MESS, and Nestopia. It is designed to be run in an arcade cabinet and controlled with a joystick or spin dial.
A PHP framework.
A simple lock manager.