Well when I was little (pre-grade schooler) I did the usual let's stick things in the electrical outlet...right up to the point where I got my first taste of electricity .
Rode my pedal fire truck (the good ones made out of metal) and later on my bike off of various hills, jumps etc (should've never watched The DUkes of Hazzard or Bullett

)
Me and my friends used to ride around on trikes, quads, snow mobiles and dirk bikes parallell to each other with the guys on the back of each bike using baseball bats as swords and metal garbage can lids for shields trying to knock the other guy off. We were safety conscious though

always had helmets, only did this in open fields, and the drivers were strictly off limits as targets.
Usual firecracker stuff liek at a picnic I temp lost the hearing in my left ear (about 2 hours) an my frind almost lost the tip of his finger and thumb from a fire cracker with a surprisingly quick fuse. Numerous times my friends and I have almost burnt our hair off with home made rockets that didn't light off until we were up on top of them to see what went wrong

(there's a range safety message in there somewhere, I'm sure).
One time a friend and I got this old beat up 1/48 scale model of an F-111 and put it on a ramp with 2 Estes C sized rocket engines in the back (1 for each engine of course) and lit them off. It would've flown too except only one engine lit and the off axial thrust started to point it back in our direction

Thankfully the uneven thrust swung it past us and eventually just had it spinning on the ground (after it crashed back down the 2 feet it achived in height) and spun around with parts flying off of it in all directions...then it kind of melted/blew itself apart when the parachute charge went off...
"Damn crazy kids" I believe was the comment from the neighbors
