This summer, a few dozen Boston-area high school students chose to spend their mornings toiling away with a variety of materials to create working marvels of engineering.

They’re this year’s participants in the Engineering Design Workshop, a month-long program that gives teenagers a hands-on experience with the joys and challenges of engineering. Director Ed Moriarty, an instructor at MIT’s Edgerton Center, hesitates to categorize the workshop’s main goal as anything other than “fun.” But if students manage to learn a few basic engineering principles along the way, then all the better, he says.

Twenty-two students make up this year’s cohort, a number that has grown steadily over the last decade. Most come from the John D. O’Bryant School of Math and Science in the Roxbury Crossing neighborhood of Boston, but the group also includes several students from other local high schools. Moriarty says the camp is run on a “pay-what-you-can” basis, with the majority of students attending for free.

Projects developed during the program vary widely from year to year, depending on the interests of the students. None of the activities are prescribed; instead, students take part in brainstorming sessions on the first day, and things develop from there. Typically, the “counselors” — a mix of undergraduate and graduate students from MIT and other local universities — present a few ideas, and the students decide which projects they’d most like to work on.

“I don’t care what they end up doing. I just care that they care,” Moriarty says.

This year, the 22 students divided themselves into five projects: a modified Razor scooter, equipped with a motor and brakes; a sound system of giant tower speakers; remote-controlled “anything” (which ended up including cars, fish, birds and even a flying turtle); a mosaic tiger meticulously assembled from pieces of stained glass; and an electric cello.

Each student is allotted $100 to spend on materials for his or her group’s project; this way, projects that attract more students have a larger budget to work with. Counselors help them purchase supplies online and work with them on the construction from the ground up.

Moriarty and the counselors agree that it’s mostly about the process and not the final result — but still, the workshop produces some impressive finished pieces. The modified Razor scooter can attain speeds of up to 30 miles per hour. The stained-glass tiger is slated to be installed in the lobby of the O’Bryant School during a special ceremony this fall. And last week, on the morning of the last day of camp, a happy group of campers listened to music on the finished pair of booming tower speakers.

Ixchel Garcia, a 15-year-old sophomore who helped build the speakers, says the camp has reinforced her desire to pursue engineering as a career. When asked what her group would do with their product, she said they planned to leave the sound system as a gift for the lab. “MIT gave us this camp, so we wanted to give them something back.”