I made a dim "flashlight" using an indecasent light with wires on it taken out of a VHS rewinder, cellophane tape, and two D-Cells, and a metal strip from said rewinder.
It's very dim (like you-can't-notice-it-from-5-meters-away dim) but I pretended to have little adventures around the tiny house I used to live when there are regular power cuts around 12 hours a day in the mid 90's.
I can't remember if I AA modded my VMU or built an SNES->PC adapter first. Though I'm sure I've done something before either of those.
edit: oh wait, I remember good fun had in high-school modding pens so that they squirt water/ink/whatever you put in them. Good fun. Could get really good distance, too. Best was replacing an unsuspecting teacher's pen
Installed a modchip for my ps2 so I could play my imported Final Fantasy 10 international. At the time FreeMcBoot didn't exist (either that or I was just to negligent to notice its existence) and SwapMagic was not going to cut it.
To Heck and back again! Actually, I was just busy with my real-life business. Ryerson University rejected me after making me pay $200 total for processing , having a hard time at school, having even harder time keeping a special relationship afloat... But anyway, I'm doing alright.... I hope.
Back on topic: The "flashlight" had no power switch, it was a closed circuit until the battery died about a week or two when I built it.
I first built a portable N64 by taping a portable TV to my controller and having the console + battery cluster + games in my school bag. This is going back 1998 now. Eventually I got banned from bringing it in because I was causing a disruption and people thought it would get nicked or broken and then it went back to being an ordinary N64 until it was sold. This probably pre-dates nearly all portables made but it was by no means elegant. My first true portable didn't happen until about 2003, which was a gamecube. That gamecube was recycled into another more elegant portable and from there, I guess my portable gamecube work took off