When I was 4 - 18 years old:
I made, and wired headlights and taillights on my skateboard.
I made a real bio-oxygen tank.
I caught lizards, spiders, bees, caterpillars, worms, beetles etc.
I tried reviving a dead fly with a battery charge.
I taped bottle rockets onto paper airplanes.
I made a miniature satellite dish (And I listened to people's phone conversations).
I was trying to make a go-kart with my brother, we had the wheels, but didn't have the frame!
I tested brake systems on a iron board strapped on skateboard; at the expense of my friend who got a lot of bruises... on a steep hill.
I made a device that lit a bulb (dear my door) when someone was coming near by.
I did a little "phreaking" back in the day.
I caught a snake, even a crawfish and brought 'em home.
I blew out the circuits in my house countless of times.
For those rocket-system toys, I made a little capsule inside the rocket and put a bunch of bugs in there just to see if they'll survive the intense g-force of liftoff.
That's all I remember for now... (I'll be back every now and then)