Aside from the lawn darts, chemistry sets, clackers, the Thing maker (creepy crawlers), shrinky dinks, and other assorted things a kid in the '70s could get into...
Homemade bombs, Molotov cocktails, homemade smoke bombs, bottle rocket wars, calcium carbonate + water in a small container and a spark = boom, and several very large neighborhood fireworks shows.
All this led to .... 6 years as a professional pyro (seriously). Of course, the fireworks danger wasn't enough. I had to light them off of buildings like the Space Needle (yes, climbing around the exterior of the building), barges (nowhere to run), and from the ceilings of sports arenas. I leave it up to you to figure out how we got up there schlepping explosives.
Guess I had a death wish when I was young. My last show was at the Space Needle on New Year's 2000, when there was a terrorist threat to blow up the building during the show. I was on that building, wondering if a truck was going to crash into it to blow it up.
I decided I had a good run with no serious accidents or injuries, so it was time to hang my hat up before I had a bad memory.
Good times. 8-)