I have a bunch of electronic trinkets that I keep in a closet and periodically drag out and tinker with after a long time. I don't think I'm a genius this is literally just how I keep from going insane after working on really hard stuff at my day job. I love learning how things work like NFC, Smart Cards, Arduino control with sensors, stuff like that.
I used to do Dreamcast stuff and I set it aside for over a decade but I kept all the hardware, and recently picked it up again for a few days.