There's a cool project called "GNUstep Desktop" that brings together many old GNUstep technologies, and a few new ones, to provide an entire integrated desktop. We gave it a whirl and are pretty impressed!

The "McLaren Synth Kit" is an Objective-C framework for using MIDI and Audio on Linux computers with the GNUstep programming environment. It is distributed as a project including libraries, headers and example programs at https://github.com/mclarenlabs/libs-mclaren-alpha. You can use it to experiment with sound synthesis for your own personal projects. The project is designed to provide ready-to-compile examples after you clone the repo.