I have fun tinkering with my electronics either to fix them or enhance them in some way. The display on my Game Gear currently doesn't work and I'm thinking I might need to replace it's capacitors. Should be a fun project!
I've not messed with AV mods yet but I've been considering doing something with my 3DS so I can capture footage and screenshots from it. I still haven't decided if I want to try a hard mod capture kit or a soft mod with custom firmware. :)