I love silent discos, but who wants to buy all those expensive headsets?
The idea here is that each attendee connects to this site using their own phone and headphones. They can scan the QR to join quickly. Each station has a different theme. Tap the icon to change channels. They can keep their phone facing outwards, either in your hand or using one of those holders that strap onto your arm for running (you can sometimes get them at the dollar store) so everyone can see what station they're on. Then dance!
The synchronization across phones isn't perfect, but I've found in testing that when you're dancing, no one notices or cares :) Also note that all radio stations will be streaming constantly while the page is open (to avoid hangs when changing stations), so if you aren't actively using it make sure you close the page to save data and battery.