Currently on exhibit at the MIT Museum, the Paradiso Synthesizer is the world's largest modular synthesizer built at home by Joseph Paradiso over 14 years (1974-1988). You can play it online through the web interface PATCHWERK, which was developed to enable remote users to control the massive synthesizer.
When you turn a knob or flip a switch on the PATCHWERK site, the corresponding knob or flip is mechanically turned or switched on the Paradiso synthesizer and, when someone at the museum changes a setting, you see it, too. You may have to wait in a short queue before you get to control it but it's thrilling to interact from afar with something so complex. It's worth the wait. BP