This post combines two things we love: inventive geeks and vintage Macs.
Peter Jungers and Josh Burker worked together to write several HyperCard stacks to compose their music, which you can listen to here. That's a trio of 68K Macs you're listening to (though it reminds me of a scene from Suspiria).
On their site you can listen to all of the music, watch a video of the Macs in action and download their HyperCard stacks for use in your own weekend projects. Well done, Peter and Josh!