By Nicole Lewis

Shoppers at a Macon, Ga., grocery store were going about their business when a cellist suddenly started playing a selection from Bizet’s “Carmen” in front of the clementine display. As three violinists waltzed past the lettuce and pears to join him, people stopped, stared, smiled, and took photos. One little boy tapped out a few notes on some plums. A round of applause erupted after the last dramatic note.

The surprise performance, by members of the Macon Symphony Orchestra and the Robert McDuffie Center for Strings at Mercer University, is part of Random Acts of Culture, a program of the John S. and James L. Knight Foundation, in Miami, and part of its revamped approach to supporting the arts.

“The idea is to get the artists out of the symphony and into the streets,” says Dennis Scholl, the foundation’s vice president for arts and the program director for Miami. “It reminds people how classical performances enrich their lives.”

Random Acts of Culture came about after a friend sent Mr. Scholl a link to a YouTube video of a surprise outdoor performance in Valencia, Spain, which encouraged people to take a different view of opera. “I watched it and said, 'Wow,’ ” recalls Mr. Scholl. “What can I do to re-create the looks on those people’s faces in America?”

Since October, seemingly impromptu opera, dance, classical music, jazz, and poetry performances have been held in several cities around the United States, at airports, department stores, a farmers’ market, libraries, malls, and a children’s museum. Now at 249 Random Acts and counting, the goal is to reach 1,000 by the end of 2013 in eight of the cities where the Knight brothers have published newspapers. The foundation expects to spend $240,000 to organize events with local arts groups.

With audiences for classical performances shrinking, Mr. Scholl hopes the Random Acts of Culture might be a way to attract new supporters.

For some arts groups, the strategy is already working. “Opera singers spend their lives being onstage in front of 2,400 people politely watching them from a distance,” says David B. Devan, general director of the Opera Company of Philadelphia. “Hearing someone hit a high 'C’ in the hot-dog line gets rid of that stuffy perception of opera.”

The visibility and good will generated by the events have spurred some of the opera’s major donors to increase their gifts; one donor went from contributing $15,000 to $25,000 Mr. Devan says.

Surprise is a key element of success—Mr. Scholl says the “unexpected stays with you”—so performers don street clothes and pop out of the crowd. This was no easy feat at the programs’s largest event, involving more than 650 choristers singing the “Hallelujah Chorus” from Handel’s “Messiah” at a store in Philadelphia. The performance has generated more than 7 million hits on YouTube.

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