Mmmm, forgot about my rocketry and various explosive experiments. I got back into it just before Astronomy 'rescued' me and had a few unexpected catastrophes but my best was back in secondary school where I was a lab assistant. Access to the chem and physics labs which also had a small Myford lathe. Me and another guy built a sulphur\zinc powered rocket about 6 feet long along with some other smaller ones. Took the whole lot down to his dads farm and set up a launch rail mast. First couple of rockets went ok but the 6 footer went about halfway up the rail and then Krushniked'. A krushnik is when there is a cavity in the fuel load and the burn goes internal and explodes. Basically blew the mast and everything thing around it for about 20 meters flat, Fortunately we were dug in about 50 meters away but it left our ears ringing for days.
I ended up running New Zealand Fireworks Display Company with another couple of people. Sideline business to my real job. Used to do all the display choreography and electrical layouts. I could explode $20,000 in 6 minutes. hard work but fun !!
Sounds a bit like to be a 'geek' you really need to have dabbled in explosives ..
I've got lots more stories on explosives gone a bit wrong but really need to sit down with a beer or two for a proper belly laugh. Suffice to say I still have all my fingers and eyebrows which is considered unusual in that 'profession'.
Built a Van de Graaf generator, and a bazooka ..
And a serious crossbow using an automotive leaf spring ..