rucola
Rucola is a light weight framework that helps you write RubyCocoa apps. It allows you to build, test, and deploy applications using rake commands, eliminating the need to use XCode for the most common tasks.
APIdock
APIdock is a web app that provides a rich and usable interface for searching, perusing and improving the documentation of projects that are included in the app.
GCDrawKit
Flexible and powerful architecture for vector drawing applications
aptiva / activerecord
An objective-C implementation of ActiveRecord