Here's something you may not know about the sharks at the National Aquarium in Baltimore: They're often up at 1 a.m., drifting aimlessly like long-finned insomniacs.
But you'd have trouble nodding off, too, if occasionally dozens of Girl Scouts held sleepovers in front of your tank. After all, the last thing anyone wants to do at a sleepover is, well, sleep.
That goes double when the overnight stay is at a popular venue most people never get to visit after closing time.
As families and groups look for cost-friendly diversions, many are waking up to the idea of camping in at a local attraction. Bolstered in part by the popularity of the Night at the Museum films, venues such as the National Aquarium, the Maryland Science Center and Port Discovery are seeing steady numbers of patrons, mainly Scout groups, willing to pay to sleep on their floors.
They join many national attractions that offer overnight programs, such as the International Spy Museum in Washington, the American Museum of Natural History in New York, the Pacific Science Center in Seattle and the San Diego Zoo (which includes adults-only sleepovers).
The Smithsonian Institution in Washington, which is the centerpiece of this year's film Night at the Museum: Battle of the Smithsonian, holds sleepovers at its National Museum of Natural History, where it shows the film at its IMAX theater.
"These types of experiences are becoming more and more appealing to people because of the economy," said Jen Bloomer, a spokeswoman for the National Aquarium. "In general, people are taking smaller trips and paying for these types of experiences over a weeklong family vacation."
They also offer a chance to get up close and personal with exhibits at a time when people want more access from and interaction with formal institutions.
"People are looking for unique things to do at a unique venue," said Diane Bellomo, supervisor of the Science Center's Camp In sleepover program. "Our location is popular because you can sleep in front of our railings at the waterfront and watch the sun come up over the Inner Harbor. Plus, movies like Night at the Museum help us; people look at our exhibits and say, 'Do the dinosaurs come out at night?' "
It's that personal experience that museums and similar attractions are looking for to generate repeat customers, said Ford Bell, chief executive officer of the American Association of Museums. He said that sleepovers are ideal for the museum industry, because the time to get museum-goers hooked on attending is when they're children.
"You want to create this feeling of belonging so that they say, 'I want to go back,' " Ford added. "A sleepover offers a chance for very personal exposure and a chance for a personal connection."
Most museum overnights are for kids over the age of 4, and while some are pricey (the American Museum of Natural History sleepover is $129 per person), others cost about as much as a day at an amusement park (Port Discovery's sleepover is $40 for children, $35 for adults). Most provide food, but they request that patrons bring sleeping bags.
Some overnight patrons choose the event as a twist to an ordinary sleepover. Others, after hearing about the sleepovers, decide to return to venues they had visited in daylight.
"We were looking around for a local but memorable experience, and we'd gone to Hershey Park," said Kristine Westphal, one of the chaperones for a Brownie troop from Manassas, Va., that slept over at the National Aquarium. She said that the troop of third-graders visited the National Aquarium's Breakfast With the Dolphins event two years ago and added, "The Night at the Museum movies made us want to do this all the more."
Since the National Aquarium's program was launched eight years ago, most sleepovers at the attraction have sold out.
Sleepover guests arrived at the aquarium about 6 p.m. on a recent Friday, and were treated to a dolphin show, dinner and an interactive 4-D film.
They took a guided tour through places normally off-limits to visitors, including the food-preparation area, where they learned how sharks and rays are fed and cared for. They moved along a catwalk above the shark tank, the creatures swimming just inches below their feet.
"That was scary; I'm not used to being that close to a shark," said Kristy Albright, 13, of Spring Grove, Pa., who spent a night at the aquarium with her Girl Scout troop.
After visits with underwater divers, the overnighters turned in just after 12:30 a.m., sleeping on floors throughout the facility - including the underwater viewing area where sharks and rays swim close by. The event ended at 9 a.m. Saturday, just as the aquarium opened for day guests.
"It's a great experience, and I recommend it to anyone who can afford it," said John Haneklau of Manassas, Va., chaperone to the Girl Scout troop that used its cookie sales to pay for the trip. He said he preferred the overnight stay to a morning outing, adding, "It's more of a personal experience."