The video begins like so many viral clips before it: A young person, perched in a dorm room, smiling mischievously into a camera. But there's one big difference here: This video comes from Sweden, and the Swedish sense of humor has a reputation for being a bit silly. "It's almost 10 p.m.," the young man says. "And this is what happens when one person starts screaming at night."

The student opens a window, looks out over the dark and otherwise quiet campus, and lets go with a full-lung scream. I can barely count to three before, from somewhere very far-away-sounding, a few people howl right back. It grows from there: At first just two or three isolated voices at a time, each echoing across the campus, then whole groups of them, until the dark quad is blanketed in primal screams. It would be eerie if it didn't sound like it might be fun. (Okay, it is still a little eerie.) People start laughing, probably at themselves. The video shuts off after two minutes, the shouts still going.

I asked about this on Twitter and got a helpful response from, of all people, Trita Parsi, chief of the National Iranian-American Council and author of "A Single Roll of the Dice: Obama's Diplomacy With Iran." Though he cautions that his memory may be "a bit blurry," Parsi says this was a tradition when he was an undergraduate and graduate student in Sweden's university system.

"This is at the student dorms. We had a tradition of letting off steam by screaming at specific hours, usually once a week," Parsi explains. At first, he says, the screaming happened every Monday night, maybe about 6. "But it then degenerated into taking place at any time any student did the first shout," he adds. Judging by this video, that would still seem to be the case.

Parsi says he thinks the tradition began at French universities and spread from there to Sweden's. Who knows, maybe it will break into the American educational tradition?