In a real-live Night at the Museum, this Friday, April 13, OMSI hosts its first-ever adult sleepover, with about 50 guests setting out their pillows and sleeping bags upstairs in the Life Science Hall. (Sleeping pads, cots, and earplugs are optional.) Exhibits, including the new Robot Revolution, will be open, and behind-the-scenes tour offered throughout the evening will take guests aboard the USS Blueback submarine and deep into the museum’s basement.

While the event format might inspire flashbacks to grad-night lock-ins or slumber parties with Ouija boards, games of “light as a feather, stiff as a board,” Candyman viewings, and the occasional pair of frozen underpants, the 21-and-over OMSI All Night event has a few features those other things probably didn’t. There’s a planetarium premiere of a Stranger Things laser light show, and the chance to sleep inside a replica of an Arctic permafrost tunnel or in a round room full of human fetuses. Three drink tickets are included in the admission price—$130 for OMSI members, $150 otherwise—along with heavy appetizers, a midnight snack, and breakfast. Anyone sneaking in their own booze or any marijuana whatsoever will be asked to leave. (OK, so maybe it is a little like a grad-night lock-in, after all.)

OMSI’s director of events, Andrea Edgecombe, says the museum has hosted school and scout groups for educational overnight camp-ins (“Kids have an awesome time; chaperones don’t get any sleep”) and had plenty of adults-only events with its OMSI After Dark series. But this is the first time the museum has brought the two concepts together. “A few years ago, the American Museum of Natural History in New York did an adult sleepover there, and it was all over the news,” she says. “Ever since we saw that, we’ve wanted to do that here at OMSI.”

Edgecombe and her team sought advice from other museums that have hosted similar events, and added their own behind-the-scenes elements unique to the Portland institution—like a chance to explore the basement flood equipment that kicks into gear when the Willamette River misbehaves. Guests will sleep in the Life Hall, says Edgecombe, mostly because it’s one of the darkest rooms in the building. “OMSI has a lot of windows and a lot of natural light, which is really awesome most of the time,” she says. Staff (acting as chaperones, in a sense) will be sleeping there, too.

Registration is already closed for this inaugural OMSI All Night; Edgecombe says that while the museum can fit 150 for a sleepover, the team wanted a smaller group for this first run, in part so staff can interact more with the guests and get feedback on what works and what doesn’t. (Also, she notes, the smaller group can fit in the planetarium for the laser light show without it being upside-down for anyone.)

Didn’t get tickets? If things go well, OMSI plans to host another sleepover next spring and then might consider doing it twice a year with a fall version, too, plus increased capacity and possibly a chance to sleep in the Science Playground. For a DIY version, just stay home, fix yourself a cocktail, invite over some neighbors, borrow some taxidermy, and camp out in your living room while you binge-watch the BBC’s Planet Earth II or Cosmos with Neil deGrasse Tyson.