I think it's worthwhile to note if you never played with guitar pedals; they do something that really should be ubiquitous in computers; you can easily re-arrange them into different combinations to create different sounds. The basic idea is doing something that is technically/electronically, "high engineering" (problem solving with constraints) in a playful, simple way.

It's really neat to see kids thinking things out loud like, "I wish there was to apply an envelope filter and an echo to this thing I am building but it's not sound..." In education courses.