iTheater is an open source project that aims to create a media center application for Mac OS X, to fully take advantage of Apple's OSX. The project aims to integrate most media-based Mac applications into a single console (or media center).
The Open Descent Foundation (ODF) is a community for developers, who want to help to create open source programs, tools, etc. for the famous games Descent1, -2 or -3. Everyone can join the ODF if he accepts the idea of writing open source programs.
The AIGL project is a free and portable objective-C user interface library especially made for video games. It uses OpenGL to render the UI. In future releases, the whole interface will be editable, in order to make the UI blend in with any video game.
Petite is a tailor made library to develop using Objective-C, without any NeXTStep syntax. Petite is there to help people to discover Objective-C programming.
iPlay is an entire Cocoa application that provides Mac OS X users a simple way to tell the world what they are listening to in iTunes. It allow you to upload on a FTP host iTunes current track informations (title, artist, album, duration) and artwork !