How much more fun we'd all be having if only Washington's museums were open in the middle of the night.

Nighttime is the perfect condiment for deep thought. It makes the profound and otherworldly seem even more profound and otherworldly. There's a reason college kids have all-night Sartre sessions. Night gives people permission to subvert social conventions -- to talk to strangers, to snooze in public. In the case of the National Museum of the American Indian, which was open continuously from 1 p.m. Tuesday through 5:30 p.m. yesterday, the predawn hours brought out intense academics and precocious children and native peoples who had traveled far and wide to celebrate a milestone of cultural achievement.

And, of course, there are also the crazies.

At 4 a.m., just inside the Indian Museum entrance, are two practitioners of "holistic health." The woman, whose business card identifies her as "Sister Adinah 'Araunah' Grant, counselor of holiness," says they don't know what to do next so they're going to consult the water and the rocks. The man, who gives his name as Brother Bey, says, "We're just going to go outside and vibrate on the air."

What sweet vibrations there are at the Indian Museum in the middle of the night! The whole place feels just a touch subversive. The staffers are yawning and unguarded. Little kids are awake long past their bedtimes. From outside, the museum's undulating windows glow, resembling melted circuit boards. During a lull before dawn, even though the gift shops are still crowded, there are a few moments when you feel almost alone in this museum, as if you had hidden in the bathroom at closing time and came out after everyone went home.

This night opening of the Indian Museum is a one-time thing, designed to accommodate the large number of people traveling from afar. Museum officials will estimate that 24,000 people walked through the museum's doors between its grand opening at 1 p.m. and just before midnight Tuesday. Between midnight and 7 a.m. Wednesday, 3,200 more people come.

Many are American Indians who participated in Tuesday's ceremonies. They've been planning this trip for weeks and months, and they've been awake for 14 or 16 hours, and they are by now running only on excitement. Others are locals who hear about the museum's unconventional hours and pop in on a lark. They come from the opera, in business suits with pocket squares. They come from late shifts, still in uniform. A stereo equipment salesman sets his alarm for 3 a.m. so he can bike to the museum, go through the exhibits, then go back home to Capitol Hill to sleep. His hair is still matted from the pillow.

At 2:30 a.m., a young Mexica-Aztec woman named Celia Medina-Genis, 25, from San Francisco, has been going through the museum inch by methodical inch. She has been here for two hours and she has seen little more than one exhibit. At this rate, she guesses, she will be done no sooner than 7 a.m. She slept one hour Monday night, and not at all Tuesday, and performed with her dance troupe all day and she has eaten just one meal. She is nowhere near exhaustion. She is exhilarated.

"When your heart's full, your body's full," she says. "We say it in Spanish."

There's a guy in the "Our Peoples" exhibition splayed out on a couch, holding his leg over his head, with crutches next to him. He broke his foot some weeks back and in his excitement to see the museum, he hobbled too fast and too hard.

"When you're excited, you can ignore the pain," says Jeremy Felsen, 25, a Native American history buff. Two hours later, he zooms by in a wheelchair provided by museum staff, looking delighted.

Yes, this feels like a college dorm. Packs of disaffected teens make their way toward the cafe only to be told it closed at 1 a.m., sealing up all that delicious fry bread. Elsewhere, two women and a man, all young, discuss the nature of energy as if they're a late-night science club. One of the women warns the others not to "get all quantic on me." Downstairs in the atrium, there are scattered groups of people asleep on a circular stone bench.

They could go home. But why?

"It's like attending the birth of a child," says Dorothy Massalski, who teaches education at the University of Arizona and has also taught children from Navajo, Hopi and other tribes. "You stay until that birth is complete and then you rejoice in it."

Massalski says she'll be here all night. Her sandals are off and her legs are flat out in front of her on the bench, like a little girl sitting in a grown-up chair. She's watching how people relate to the sandstone circle in the middle of the atrium, which sits directly under the museum's skylight. It's considered a sacred space. Some people step into the circle, others walk reverentially around it. Adinah Grant and Brother Bey, the holistic health practitioners who both claim Blackfoot ancestry, slip off their shoes and stand barefoot in the circle.

"See? Isn't that beautiful?" Massalski says. "Why should I go anywhere?"

Brother Bey lies down on the floor, with his torso over the red stone circle, and stays there for about 10 minutes, and everybody goes on about his business, and it's really strange or really profound, depending on your point of view.

Up in the Resource Center, librarian Lynne Altstatt is taking questions from everyone. She has been here since 8 a.m., and she must lead tours tomorrow at 9 a.m. Her voice is hoarse and her eyes are about as closed as eyes can be while still staying open. There are a few staffers on this floor, and they've all been jockeying for two prime nap positions, and Altstatt has not yet gotten one. She's enjoying herself, though, in a somewhat perverse fashion. She has a slightly hysterical laugh and a big, crazy grin. A lot of weird people have been through here, she says, and they keep her awake.

"Late night brings them out," she says. There was a fellow covered in souvenir pins who said he excelled in running backward, and a guy with "really fuzzy hair," she says, who wanted to debate the appropriateness of the word "Indian." And now, here comes a fellow who really, really likes visiting museums, he says. He just wants to talk about anything at all.

He has a question about shrunken heads. How do they get them so small? he asks.

Altstatt assumes an attitude of librarian gravitas, because after all, this is the time and the place to consider weighty philosophical matters. Then she says she's pretty sure you have to remove the skull.

In the wee hours at the Indian Museum, two visitors take a break from their tour. Crowds were waiting to get into the Indian Museum at midnight Tuesday. Visitors with questions kept museum librarian Lynne Altstatt, below, up late.