CHICAGO—A honey-bee breeder, a jellyfish scholar, a stone carver and an Emmy-winning screenwriter were among 23 people awarded $500,000 "genius" grants Tuesday by the John D. and Catherine T. MacArthur Foundation here.

"It just blew me away," said Marla Spivak, a 55-year-old professor of apiculture at the University of Minnesota. "I thought they might have the wrong person." She won the grant for breeding honey bees that can restore health to beehives stricken with pests or pathogens, which in recent years have devastated U.S. bee colonies. She plans to use the grant to launch new bee-related projects.

The award winners can use the grants for whatever they wish. This year's picks were the usual eclectic mix of artists, scientists, economists and others the foundation recognizes each year.

Marla Spivak checks on a bee colony Monday in one of her labs at the University of Minnesota in St. Paul, where she researches honey-bee health. Matt McLoone for The Wall Street Journal

While most aren't well known outside their fields, this year's crop includes David Simon, the Baltimore author and screenwriter responsible for such popular shows as the Emmy-winning HBO television series "The Corner," as well as HBO dramas "The Wire" and "Treme."

The MacArthur foundation said it gave Mr. Simon a grant because of his ability to "craft richly textured narratives that probe urban America's most complex and poorly understood realities."

In an interview, Mr. Simon, 50, said that while he was honored to receive the award, he also felt a tinge of guilt. Past winners have been "people directly engaged in trying to improve the environment or trying to address social injustices," he said. "To be blunt, I'm in the entertainment industry…and my contracts are well funded right now."

Other award winners include Amir Abo-Shaeer, a physics teacher at Dos Pueblos Engineering Academy in Goleta, Calif., who is using robotics as a teaching aid; Jessie Little Doe Baird of Mashpee, Mass., who is working to revive the Native American language of Wampanoag; Carlos D. Bustamante, a population geneticist at Stanford University School of Medicine; and Carol Padden, a sign-language expert at the University of California, San Diego.

The grants, which are taxed and are paid in quarterly installments over a five-year period, are designed to give people the freedom to delve deeper into their creative pursuits and reward "exceptional people who are likely to make great things happen," the foundation says. While often referred to as "genius" grants, the foundation says it avoids that designation because it too narrowly defines award winners.

"Creativity is at the heart of this" fellowship program, said Robert Gallucci, president of the MacArthur Foundation. "The most vexing problems are not going to be addressed without creativity."

Among the Winners John Dabiri, 30, a Caltech professor who has studied the swimming motion of jellyfish

Nicholas Benson, 46, a stone carver and calligrapher working on the Rev. Martin Luther King Jr. National Memorial in Washington, D.C.

David Simon, 50, an author and screenwriter responsible for HBO's 'The Corner,' 'The Wire' and 'Treme'

Sebastian Ruth, 35, the founder of a musical academy that teaches inner-city kids. See more below

John Dabiri, a 30-year-old associate professor of aeronautics and bioengineering at California Institute of Technology, won a grant for his pioneering work on jellyfish. Mr. Dabiri determined that swimming jellyfish leave vortex rings in their wake that help them move through the water more efficiently. He is finding practical uses for this phenomenon, from diagnosing heart failure to creating more efficient windmills.

In an interview, Mr. Dabiri said he hadn't decided how to use the MacArthur money, but hoped to use some of it to keep studying jellyfish and other ocean fauna. "Our oceans are full of unknowns," he said.

Nicholas Benson, a stone carver and calligrapher who is also a third-generation owner of a stone-carving shop in Newport, R.I., won the award for his "meticulously executed inscriptional works" that "are noted for their uncompromising craftsmanship and beauty in form and line," the foundation said.

Mr. Benson, 46, still does most of his work with a mallet and chisel, even though stone carving today tends to be done by machine. He is currently working on the new Dr. Martin Luther King Jr. National Memorial in Washington, D.C.

Mr. Benson said winning the grant was a "great affirmation" of his work. "I toil away at this very, very odd little business, and I get great kudos from my clientele," he said. "But there are times when I wonder if anybody really gets what I'm up to here."

Another winner was violinist Sebastian Ruth, 35, founder of Community MusicWorks, a Providence, R.I., music academy that works with disadvantaged inner-city kids, teaching them how to play string instruments. The foundation said Mr. Ruth "and his fellow quartet members have taken up residence within the inner-city community they serve, in keeping with their vision of music as a nurturing neighborhood necessity similar to a library, a church or a health clinic."

This year's MacArthur Fellows found out over the last week or two that they had won the award and were sworn to secrecy. Before that, most had no idea they were even under consideration. The foundation's unconventional selection process involves a group of anonymous "nominators" in a variety of fields who secretly suggest candidates. A panel of anonymous judges then narrows a pool of hundreds to about 20.

The MacArthur Foundation was created in 1970 by Chicago businessman John D. MacArthur and his second wife, Catherine, and today pursues many philanthropic endeavors in addition to the "genius" grants. That program was launched after a board member proposed rewarding people "genuinely interested in research and exploration of the unknown to advance knowledge…without the annoyances and distractions imposed by grant applications, reviewing committees, and pressure to publish."

Since the first group of fellows was named in 1981, there have been 828 recipients, including this year's group.

Write to Lauren Etter at lauren.etter@wsj.com