At the end of a week of all-day dancing, the students at the American Dance Festival need to express themselves and socialize. To do so, they don’t go for drinks at a bar, or milk shakes at a diner. No — they improvise and dance some more.

The social magnet of Saturday nights at ADF is the Ark Dance Studio, a gabled old house, boarded with white, wooden planks. Students start to gather on the steps of this small, one-room, century-old building just as the sun is setting. The jam-packed weekly improvisation sessions have become one of the most popular weekend stops for many students, despite the sweltering heat and lack of air-conditioning.

“It’s kind of like a social dance,” a first-year ADF student from Virginia Beach, Aaron Burr Johnson, said. “What we do here is not meant to be performed — it’s just for the participants, kind of like going to a club.”

To watch the dancers in this high-ceilinged room is like watching a room full of ants, scurrying this way and that, telling personal stories that occasionally intersect. Almost every square foot appears in motion. In one corner a pianist, percussionist, and xylophonist jam alongside the dancers in a continuous wordless conversation.

“We’re all feeding off each other,” a 25-year-old dance teacher and ADF student, Alison Hart, said. “There are moments when you are totally internal. And sometimes you are absorbed partnering in a duet. Then suddenly you start moving across the whole floor with great strides and it’s like the whole room is breathing together, using the same beat, the same rhythm.”

These improvisational jams include a lot of contact, which becomes the starting point of other movement. The physical barriers here are lower than in most other social settings, and the intimacy among strangers fluctuates with every heartbeat — touching is okay; speaking is not.

“If somebody tries to make contact with you, there is a given understanding that you can either give into it or move away, and nobody’s feelings will be hurt,” Ms. Hart said. “When you do start partnering, it becomes very private and you’re very vulnerable. You’re sweaty, you smell, someone’s head may suddenly be in your armpit, you put your weight on someone, and may find they let you fall to the ground.”

It is precisely this unpredictability and the constantly shifting dynamics that attract so many students week after week. And it’s not just students. Duke University faculty and dancers from some of ADF’s performing companies are regulars, too — dancers from Shen Wei Dance Arts, Pilobolus Dance Theatre, and the Trisha Brown Dance Company have all made appearances this year. The language here is truly universal and resonates as much in Durham as in Buenos Aires, Eastern Europe, or beyond.

“Sometimes people come catapulting at your head; people can be reckless,” Mr. Johnson said with amusement. “I’ve gotten mad sometimes, but not really vocally or physically. I probably just stomp loudly off the floor and am sure the other person doesn’t even notice.”

Such encounters can help dancers find their own voice. They explore motion and meaning in tandem with others. “I have fallen in love with improvisation because it allows me to form my own technique,” Ms. Hart said. “Every feeling is a new and immediate feeling, and I can make my own decisions in the here and now. This is about as free as you can be in your body.”