When at festivals last summer, there were thousands of used nitrous cylinders littering the ground, so I collected up a couple of sack fulls, bought a MIG welder, and proceded to make sculptures from them. Never done welding before, but it's come in handy for a few other things (and I love my huge red leather gauntlets).
I've found over the years that I have no use for a toolbox, as my tools spend more time out of it than in it, and besides, they wouldn't all fit, so I got an old office desk and filled all the draws (5 on each side and a big one with 2 layers in the middle) and shelves around it with tools. My screwdriver has 60 bits, and there are only a couple I've not used.
Fixes of notable mention: A 19" monitor that lost all green signal, fixed by switching parts of the green circuit with the red, and tracing along it until I found the broken component. Soldering a broken surface mount scale connector of over 100 connections in a laptop computer, using pipe screen as solder wick. Stripping the Briggs and Stratton 1.2HP petrol engine on a non functioning cylinder lawn mower at the age of 12, and getting it working on the first pull of the pull-crank.
My childhood heros are Richard Scarry's Mr Fixit (The Fox), and Ted Glenn from Postman Pat (theme tune 'Leave It With Me'), and I was reading technical manuals and understanding how machines worked before I could understand the writing. I had my spacial awareness tested as part of an assesment by an employment psychologist, and scored higher than 99% of university entrants for art, design and engineering courses (the test didn't have a 100%). When I was a child my parents had to go to great lengths to hide any screwdrivers, or I'd disassemble the VCR to find to out how it worked (it still worked after I'd put it back together again, in fact half the time I can fix things just by taking them apart and putting them together again).