Or "What one does when one should really be doing something useful instead".
I was always interested in electronics, and built my first obligatory crystal set when I was about 10 I think. Getting those "cat's whiskers" to perform like a diode is probably a lost art these days! But I remember the big project when I was 12 or so, was a three VALVE radio. It worked off batteries - the dry cell multi-tapped HT battery which put out a maximum of 120 Volts, the Lead Acid "accumulator" which sometimes reached 6 Volts (had to be recharged at the local radio shop), and the all important "Grid Bias" battery multi-tapped up to 9 Volts! The valve bases were Bakelite with screw terminals for the connections. I can't remember if I ever got it to work, but it covered most of my bedroom floor. They don't make 'em like that any more!
From age 6-12 I was also fairly interested in explosives (product of a war time upbringing?), and regularly managed to set various things on fire (Bedroom curtains - at least two garden sheds, etc.). The chemists would never sell us Saltpetre for gunpowder, but potassium chlorate cough tablets made a good substitute. My friends and I made various "bombs" from Acetylene, potassium-tri-iodide (I think), and gunpowder of course (which we would detonate with fuse wire after winding a ball of string around it - each layer soaked in wax) - play's havoc with a metal dustbin.
During my apprenticeship I fell off motorcycles on many occasions, and later enjoyed driving a variety of cars sideways, and fixing them up when they broke or to get round corners faster. A picture of one much loved car (a ford fibreglass bodied "special") can be found here. Then I started to enjoy some sport after getting over the compulsory Rugger, Cricket, and "Athletics" that I suffered at school. I liked Squash, Water and particularly Snow Skiing, and enjoyed learning to fly various types of aircraft (particularly night flying for some unknown reason).
Then I got hooked on PCs, which as all readers will know, become remarkably time consuming for a device that is supposed to improve your efficiency. The story to date in covered in excruciating detail in PC Pages.