Worst one I ever had (and I've only told like 2 people this) was when I was in fifth grade, I was very immature in pretty much every way you can imagine. Especially when it came to girls, sex, any of that. Anyways, we were in fifth grade health class, the teacher turns on the projector and slaps down a transparency of the female nether regions. Being a rather book smart kid who asked questions about EVERYTHING, I couldn't hold back and threw my hand up. I got a hunch the teacher knew something bad was coming cause he tried to tell me to wait for the end of the lecture before questions, but I wouldn't wait. Finally he said go ahead. So I ask "What's a vagina?" but pronounced it like the name Gina. So phonetically va-gee-na. There was an incredible silence followed by a massive outburst of laughter with me sitting there in the middle trying to figure out why people were laughing and what I had said. It was horrible. To this day my face turns red when I think about that.
Another one, I was sitting on the school but in like 4th grade and the kid in the seat across from me was like "Ah, he's got a boner!" and pointed at my crotch. I had no clue what he was pointing at or what a boner was so I just sat there like nothing was going on. It hit me like 3 years later what he was talking about.
If women can have a closet full of shoes, I can have a safe full of guns.