A collection of open source and public domain software for Java, XML, and Cocoa, primarily. Some projects: ThreadWorker, Xmlizable, Base64, Tabu Search.
The AbiWord word processor is a full-featured cross-platform word processor.
MOKit is a Mac OS X framework that is based on the Cocoa frameworks. It provides additional classes and extensions to standard Cocoa classes that can be used in Cocoa applications.