I was about 8. My brother and cousins in their late teens (almost certainly stoned) were hanging out with me while our parents enjoyed a few drinks. This was normal at the time. There was even indoor smoking then!
Anyway, I'm reading the D&D Monster Manual I got for Christmas and am telling them about dragons. I explain there are dragons that can shoot out clouds of poisonous gas and accidentally let a fart go that I'd been desperately holding in for a while at that point.
Still the biggest laugh I've ever got and it really was an accident.
We were not the kind of family where anyone let on go in public so it added to the hilarity.
I was on vacation with my dad, in a mediteranean country. Me and a friend went to pick prickly pears. Because we did not have a bag, we used my fathers cap. I think he was not amused when he tried to wear it again.
I made a fireplace out of wood for my playhouse/shed. It worked about as well as expected.
(In my defense it was a sort of laminate, so I didn't clue in what it really was until it was too late. I ended up causing around $2000 dollars damage, which was a fair chunk of money in the 70's.)
I'm told that as a young child when I first started learning about "the birds and the bees," I said something about how "isn't it amazing how the sperm finds the egg right through the jeans?" (I confused "jeans" with "genes.")
The first time I belched at dinner. It was just my parents and my sister. We hit one of those quiet pauses in the conversation and I let a tabling rattling belch go without thinking about it. My mom couldn’t stop giggling that night.