History buffs rushed at the chance for an adult-only night at the museum next month.
The firstSleepover for Grown-Ups at the American Museum of Natural History on Aug. 1 sold out in just under 20 hours, with all 150 tickets gone by Wednesday morning.
Registration opened Tuesday afternoon and only 40 tickets were left by the end of the day, according to Brad Harris, senior director of visitor services at the museum.
"When we got in today, 38 people were in the phone queue waiting to register," Harris said. "By 9:05, they were all gone."
The $375-per-person event is modeled after overnight visits for kids. Those nights have attracted some 64,000 people but limit age and adult-to-children ratios.
"We know the adults are just as intrigued," Harris said.
During the adult sleepover, ages 21 and up, participants will get dinner with wine and beer and see live jazz music. They can also visit special exhibits, including "Spiders Alive!" with more than 20 species of arachnids.
There will also be a fossil fact-finding tour by flashlight and a midnight viewing of the "Dark Universe" space show. And they will sleep on cots under the big blue whale.
Harris said museum-goers have been suggesting a grown-ups-only event for years. The space covers four city blocks and sleepover participants may end up wandering alone in many exhibitions.
"It's a unique experience," he said.
Despite the test-run's popularity, Harris said it would be difficult for participants to sell tickets to eager adults who missed out on registration.
"There's a whole bunch of hoops to run through," he said, including signing wavers.
It's too soon to tell if there will be more adult sleepovers in the future. This event is just a pilot, Harris said.
"We want to test it and see how it works," Harris said. "It would be great to do more."
Follow Anna Sanders on Twitter @AnnaESanders