I love synthesizers. I've been working on this project for over 5 years. It's designed so that anyone can use it to learn to solder using the project's super nice assembly instructions -- even for people who have never made anything before. It comes with a way wonderful synthesizer that can make music right away with its built-in touch keyboard and amp/speaker.
If you like, you can download any of the other 10 synthesizers to make lots of very different music, sounds, and noise! To add another synth, the completely open source ArduTouch project uses the free Arduino software to program it (using Windows, Linux, or MacOS).
The free ArduTouch Arduino library has many examples that serve as a tutorial for learning how to create your own synthesizers.
And, for people who want to take things further, the ArduTouch project is designed for beginners to learn the basics of Digital Signal Processing for creating music, sound, and noise from computer chips (microcontrollers).