The Infinite Corridor is mostly quiet on Sunday afternoons at MIT except for faint rhythmic slapping sounds where the hallway starts to approach the lobby of Building 10.

And that’s when a unicycle zips by.

Where the corridor spills open to the lobby, orange plastic clubs fly through the air. Red, blue and yellow rings bounce off the walls into skilled hands. And a group of jugglers toss a rainbow of balls up, around and around.

Students walking by glance over, sometimes stopping to gawk.

This isn’t a new sight at the Massachusetts Institute of Technology. In fact, it’s been a regular occurrence for almost 50 years after the MIT Juggling Club, which started in March 1975, merged with a unicycle club that started in 1973.

Arthur Lewbel, 66, an economics professor at Boston College, was an undergraduate at MIT then. An avid juggler since he was a teen in New York, he knew he had found his match when he saw fellow student Andy Rubel’s unicycling group. They met as “adjacent” clubs, then merged, meeting ever since mostly in the lobby, but when the weather is favorable outside at Killian Court.

Decades later, the club is still going – the oldest juggling club in continuous operation, Lewbel said – with a weekly drop-in crowd, no official membership roster and no dues. It’s open to students and the community of Cambridge and Greater Boston.

Pre-pandemic, the group attracted about 15 jugglers and unicyclists a week; it’s been more variable since, with sometimes just a small core of dedicated jugglers showing up.

One of those is Stuart Ryerse, 28, who came to Boston to attend the New England Conservatory of Music.

“Just look at it,” he said, a smile forming as he described his love of juggling, a skill he began to pursue at age 13. “It’s very cool. I just had to be able to do it.” Much like Lewbel, he came to juggling on his own through curiosity and magic.

Lewbel said as a boy, he was teaching himself magic from library books and practicing in front of the mirror at home, but was bored with the techniques of misdirection.

“After I finished all the magic books at the library, the next book on the shelf was juggling,” he said.

As Lewbel and Ryerse tossed plastic clubs through the air in a seemingly effortless dual juggle, Somervillian Ellen Brill helped three novices and one semi-novice work through the basics. Brill, who began juggling as an undergraduate at Wellesley College under the mentorship of a professor, said she loves working with newcomers and teaching. She starts the newcomers with good habits (or tries to break already-formed bad habits), giving advice along the way – much of which could easily be metaphors for life.

“Start with beanbags so nobody gets hurt,” she urged, “including the teacher.”As a juggler performed an under-the-leg toss, Brill explained another juggling- and life-lesson: “There are things that look hard that are easy and things that look easy that are hard.”

Off to the side, Nina Dubinsky of Newton practiced her new skill, which she had started with a juggling book. “I wanted to learn to juggle for a long time,” she said. “I’m 59 and I thought if I don’t learn now, I’ll never do it.”

It was just her third time with the group, and she still felt a little unsure of herself, but she liked the camaraderie. “I can juggle with little bouncing balls, which I never imagined before.”

Next to Dubinsky, Tom Cahaly, 18, a student at Northeastern University, alternated between practicing his juggling and his unicycling, skills he’s been working on for four years.

“The unicycle was a Christmas gift I asked for,” he said. “Best Christmas gift ever.” After starting with juggling at age 14, he convinced his parents that unicycling was the logical next step. But it wasn’t until he heard about the club that he found his people. “I had never met anyone else who juggles, so it’s nice to have a juggling community.”

Lewbel said that’s exactly why the club exists – and continues.

Across the years, it’s attracted a cross-section of humanity: young, old, students, professors, people who changed the course of the world, artists, writers, performers and the juggling-curious. Lewbel said among the more famous drop-ins to the club have been mathematician Claude Shannon, an avid unicyclist who dabbled in juggling before attending the club. While with the MIT Juggling Club, he developed the first mathematical theorem of juggling: (F+D)H = (V+D)N, in which F equals how long a ball stays in the air; D equals how long a ball is held in a hand; H equals the number of hands; V equals how long a hand is empty; and N equals the number of balls being juggled. Basically, one side of the equation tracks how much time hands spend juggling balls; the other side tracks the time balls are juggled.

Father of high-speed photography Harold “Doc” Edgerton was another famous attendee of the club as an MIT professor. Though Edgerton didn’t participate, he would drop in to invite jugglers to his studio.

“You have real MIT ‘geek’ types but you may also have some artist types,” Lewbel said. “There’s a nice range of where people are coming from.”

Every week, Brill and others with a penchant for teaching urge those who hover hesitantly nearby to pick up beanbags and start with the first toss. At the end, regulars remind the newcomers to keep coming back.

That works for Lewbel.

“It’s pretty gratifying that something I started long ago is still running,” he said. “It fills a void. It shows we did something right. You don’t need dues. You don’t need members. You just need to meet at the same place and time every week.”

And they will: every Sunday, from 3 to 5 p.m. where the Infinite Corridor opens into the Lobby of Building 10 at MIT.

For information, visit mitjuggling.club.