Meet the CircuitMess Jay-D: a DIY DJ Mixtable kit that teaches your kids coding and electronics. It comes with drag & drop coding but more advanced users can graduate to C++. As your kids put this together, they will learn soldering and other skills.
You can use your Jay-D to play multiple music files simultaneously, add equalizers, and program a custom light show. It has 144 individually-controllable LEDs. It ships with a TFT LCD screen knobs, switches, and everything you need to put it together.