I woke up Saturday morning next to a large jar of something disgusting. “Agg, worms!” I exclaimed. “Actually, those are krill,” explained Colette, sitting up in her sleeping bag. “They pretty much form the foundation of the ocean food web,” she added, paraphrasing a label on a nearby wall.

That was just one of the many things I learned while camping overnight at the National Museum of Natural History, which, like many D.C.-area institutions, offers folks the opportunity to spend the night for around $135 a person (see chart). Despite the hefty price tag, these programs — which include an evening’s worth of educational activities — are wildly popular and sell out quickly.

Why are people so eager to sleep on an uncomfortable floor in a room full of strangers? And why are they paying to hang out in a museum that’s usually free? I had no idea, which is why I enlisted my friend Tori, 36, and her daughter Colette, 9, to join me on this sleepover and find out.

The three of us arrived at 7:30 p.m., just in time for the official briefing. As we entered the museum’s main cafe, we were given a supply kit with a flashlight pen, a workbook and a sugar cookie in the shape of a dinosaur. Brigitte Blachere, a Smithsonian Associates program manager, called us to order.

“Tonight, you’ll be going on an extreme exploration,” she said, explaining that we would be following the directions in our workbooks to 11 stations around the museum. At each station, we’d complete a few tasks to earn a stamp, and if we got all 11, we’d be official Smithsonian Junior Explorers.

Before she let us go, Blachere had the kids make a pledge. “Repeat after me,” she said. “I promise. To have fun. And to make sure. My adult. Participates in all the activities. And puts away their cellphone.” The kids shouted that last bit with zeal.

It was 8 p.m. by the time we were let loose in the museum, which gave us about three hours to complete all the tasks in our workbook. We raced to our first assigned zone: Mammal Hall. Task No. 1 was to find examples of “extreme” mammals, such as the largest living rodent. Tori and I roamed the 25,000-square-foot hall searching for giant rats for about 10 minutes before Colette told us the answer she knew all along.

“It’s a capybara,” she said. “They live in South America. Dad ate one once.”

Even with Colette’s help, we were well behind schedule when we got to the next station, the “Human Origins” section of the museum. A museum volunteer gave us our mission: “You’re a hunter-gatherer and you have to collect plants and animals for your tribe.” The food was pictured on cards scattered around the exhibit.

The cards were pretty easy to find, and we gathered more than a dozen in just a few minutes. “This is a lot easier than the first section,” I said. I was wrong. When we turned in our cards, the volunteer informed us that we had just poisoned our entire tribe.

“This is oleander,” she said, pointing out a card depicting a plant with lovely pink flowers. “It’s highly toxic.”

She sent us back into the wilderness to try again. We eventually succeeded at the task, which earned us a chance to chuck a spear at a cardboard cutout of a buffalo. After a few of her throws fell short, Colette ran up to the buffalo and clobbered it with the spear.

“Colette!” I yelled. “That’s cheating.” “Maybe humans evolved to cheat,” she replied.

Taking Colette’s quip as inspiration, Tori and I assessed our situation and realized there was no way we were going to make it to all of the activity stations. So instead of following the directions in the book, we decided to wander around and look for the activities that seemed the most fun.

This turned out to be a great strategy, one that led us to a marine biologist magician who seemed to make specific fish appear on his socks, a darkened exhibit full of skeletons that we explored by flashlight, and a station where we attempted to eat marshmallows like a T. rex — without using our hands.

It was about 10 p.m. when I parked myself at a table with kids making totem poles out of paper towel tubes. A woman explained that we would be modeling our totem poles on the ones created by American Indian tribes from the Pacific Northwest, but as far as I was concerned, the main point of this activity was sitting. I was beat, and so were the two 12-year-olds at my table.

“Why are we getting sleepy?” the boy asked.

“I don’t even know,” the girl replied. “Every time I learn, I get sleepy.”

As the two decorated their tubes, I noticed their father peering intensely at his lap. He was on his smartphone, I realized. Cheater! Luckily for him, his kids were too involved in coloring to notice and I, pretending to craft in order to sit, was certainly not going to turn him in.

When activity time wrapped up at 10:45 p.m., my team had completed only seven of the 11 stations. I surveyed a few other adults, and most teams had similar results. “I don’t think there’s a prize or anything,” one kid quipped.

It was time for us to pick the places where we’d bed down for the night, and the moment was fraught. I knew we didn’t want to be anywhere near the perpetually squeaking escalators, and any spot too close to a bathroom was sure to be subject to night-long foot traffic. We settled on a corner of an exhibit about the Arctic Ocean. There was a little more taxidermy present than I would have preferred — a polar bear loomed over us, and birds peered out at us from glass cases with little beady eyes. But the semi-privacy of three partitions was unbeatable, so we set up there.

Despite my strange camp companions, I fell asleep almost immediately.

The next morning, I padded through Ocean Hall and took a look around. Though I would have preferred to sleep in my own bed, there is something undeniably magical about being in a quiet, dark museum. Mummies, animals, skeletons — they all take on an eerie luminescence, as if they might come to life. So if you have the cash and a kid, or a friend with a kid, consider spending the night at your favorite museum. Just be sure to wear comfy sneakers. And look out for krill.

Want to spend the night at a museum?

You’re in luck — there are a few more sleepovers happening as part of the Smithsonian series, and at least two of D.C.’s other museums offer overnight opportunities well into the fall. If you’re interested, sign up ASAP — these events can sell out fast in our city of nerds. (Note: With the exception of the National Zoo’s, these programs require children to be accompanied by adults and vice versa.)

National Air and Space Museum’s Udvar-Hazy Center
Saturday, $135
Age range: 8-12
Where you get to sleep: Near the space shuttle Discovery
What you’ll do when awake: Future pilots can work their way from “sergeant” to “general” by completing tasks around the museum that enhance their understanding of the physics of flight, including making kites and paper airplanes. Breakfast the next morning: your choice of items from the museum’s McDonald’s cafe.

National Zoo (family)
Various dates, $125-$175
Age range: 6 and up
Where you get to sleep: In a tent on the zoo grounds, within earshot of all sorts of wild animal calls
What you’ll do when awake: Participants get an exclusive, keeper-led tour of backstage areas of the zoo. Available tours include the Cheetah Conservation Station, Reptile Discovery Center, Elephant Community Center and Small Mammal House. Afterward, enjoy camp games and snacks.

National Zoo (adults only)
Aug. 26, $188
Age range: 21 and up
Where you get to sleep: Same as above, but without any wild children calls to wake you up.
What you’ll do when awake: Same as above, but this time the post-tour snacks include wine.

National Archives
Oct. 14, $125
Age range: 8-12
Where you get to sleep: In the rotunda next to the Constitution, Bill of Rights and Declaration of Independence
What you’ll do when awake: At this space-themed sleepover, families will get to chat with NASA astronaut George Zamka, explore the Archives’ NASA records and play games with museum educators. Then, the next morning, Archivist of the United States David S. Ferriero will make you chocolate chip pancakes.

International Spy Museum
Nov. 4, $115
Age range: 9-13
Where you get to sleep: Anywhere you want in the third-floor exhibition galleries
What you’ll do when awake: Kids and adult participants interrogate an actual former spy, and then complete a spy mission together at a simulated cocktail party. Then they split up, with kids forming small teams to complete missions around the museum, while adults surveil them from nearby.

More adventures with the Staycationer