I don't have many embarrassing stories.  the ones that I have tend to be only mildly embarrassing.
So here's a short story that wasn't embarrassing to me at the time, but it should have been.  It's embarrassing to me now.
This is from middle school years.  I was probably 12-13 years old.
This wasn't summer vacation, it was instead a school camping trip close to summer.

When I was a kid, I watched meteor showers many times with my parents.  Sometimes, we would bring sleeping bags outside and lay in them while looking up at a meteor shower.
Well, once in middle school, a teacher organized a meteor shower camping trip.  Camping trips were fairly common in my school.  Many people brought their own tents, and shared a tent with their friends, so that there would be enough tents for everyone.

For this trip, we drove out to, I believe, a summer camp location.  Somewhere far away from a city, with no bright lights nearby.
The goal of this trip was, of course, to watch a meteor shower that was happening that night.  Everyone would lay outside in their sleeping bags, looking up at the stars, hoping to see hundreds of meteors over a few hours.  If we're lucky, we might even see a fireball or earth grazer.  And while watching the stars, talk with friends about silly topics.
I was part of the nerd crew.  We cared about stuff like meteor showers, and we didn't care much about socializing with everyone else.  So when we set up the tent, we set it up away from everyone else, close to the fence far away from the firepit.

As one might expect, there was a lot of normal camping field trip stuff happening.  Camping food, s'mores, camping songs, stories.  And since this was a meteor shower trip, meteor shower science talk.  Followed by a bunch of bored young teens being bored.
The songs ended and the adults left to rest in their tents.  Kids were sitting by the dwindling fire, waiting for the evening to end, and the meteor shower to begin.
At this time, one kid, along with one of his friends, came up to the campfire with exciting news.  he said he was at the other side of the field, where you can see the road through the fence.  He said he saw a completely naked lady walking down the road!
"I swear it's true!", he said.  "She was just walking past, butt-naked."  "It's true, I saw it too!", said his friend.

No way, nobody believed him.  but, the truth is, we were all in middle school.  in the back of our minds, we thought "what if?"
A few of the kids would sneak out in that direction, hoping for the exremely low chance of catching something interesting.  I Was probably one of them.
But then meteor shower time came.  It just so happened that my tent was close to the spot where we could see the road....
I was probably the most gullible kid there that day.  In one part of my mind, I knew he was just trolling us.  But in the other part of my mind, I didn't care.  I wanted the miniscule chance that he really saw a naked lady to be true, and I wanted to see one too.

So of course, led on by me (I think), my freinds and I set up our sleeping bags right there, where we could turn out head and see the road.
We in the nerd crew had all seen meteor showers before.  So we were more willing to be distracted by silly things.
For hours, while the meteor shower was happening, I was imagining "what if a naked lady really does show up?  I know it's not going to happen, but what if?"
Every few minutes, I would look at the road, hoping for a glimpse of something my puberty brain would love to see.
My freinds got bored of the idea soon enough.  But I think I kept glancing at the road every once in a while the entire night, eventually returning to my tent disappointed that there were no naked ladies.
I was told that there was a fireball once when I was looking away.

It occurred to me many years later that perhaps I really embarrassed myself there.  My friends didn't care, but what did the other kids think?  Fortunately, I don't think there was any malicious intent, no gossip, no body calling my a pervert afterward.  I bet everyone who heard the troll reacted at least a little bit like I did, and sympathized with my gullability, and my hopes and dreams... of seeing a naked lady walk down the road in the middle fo the night.

The meteor shower was cool, though.
-epigeios