Oh do I have a story.
I had an old IBM PS/1 with a 486SX-25 (me thinks). It could be considered my first retro computer. I had brought it home from a neighbor who didn't want it anymore, and started it up with Windows 95 installed on it. I had a load of fun, including putting MS-DOS 6.22 back on it with Windows 3.11, but the fateful day of going full retard happened.
Keep in mind I was around 9-10ish at the time. I was messing with the machine with the top off while it was still running, and being the dumbass I was I shorted out a few headers on the board that made the screen go all funny. I guess I shorted something that obviously was not supposed to be shorted. As a result the magic smoke exited the unit, and I was left with a giant brick. The unit ended up at the side of the road, the CRT was dumped at a tech recycling event, and the keyboard was busted by the genius known as me. The only thing I still have is the mouse, which needs it's connector to be soldered back on from an attempt to convert it to RS-232 that ended up in me just buying a serial mouse.
Fun times.
In terms of stuff just laying around that I found out was really awesome, I think one example would be my father's HP-48G calculator that I have on permanent loan. It was before I was due to go to community college for some small maths classes that I was looking for a good calculator (I think it may have actually been a bit earlier than that). I was swooning over the 68k calculators from Ti, which I have to admit, still have some small amount of my interest. I picked up the 48G with the goal of learning how it worked, and with barely any use of a manual, I had figured out the ins and outs of that calculator. It had set me on the right track to HP calculator heaven. I soon learned that the Ti calculators that I had been so interested in were absolute pieces of garbage compared to HP's offerings. Today I have an HP Prime and 50G, things I wouldn't have had without that calculator.