The royal couple arrived from Philadelphia by private train and toured the Promise Academy, where they visited an after-school program that teaches middle-school students about finances.
When Camilla, sitting at a table with about 10 children, learned that they receive real money if their virtual stock investments are successful, she exclaimed, "That's fantastic." (The children do not lose money if their investments are unsuccessful.)
Tiffany Vargas, 13, asked Charles if his multimillion-dollar line of organic foods, Duchy Originals, was on the stock market.
"No," he told her, "it's still a private company. We haven't got quite to that stage yet."
Afterward, the couple went on a terrace to get a panoramic view of Harlem, including the office building where former President Bill Clinton has an office and the Hotel Theresa, where Cuban leader Fidel Castro stayed decades ago.
Charles and Camilla also watched a rehearsal for a Shakespeare play and a basketball practice. Charles, wearing a blue double-breasted blue suit, blue shirt and striped tie, attempted two shots. He missed the first but made the second, drawing applause.
One student player, Mouhamed Mbaye, 14, said the school was lucky to have a royal visit.
Arona Pratt, the mother of another player, said: "I think it's great. My son was up all night waiting for this. They looked much nicer in person than they do on TV."
On Sunday evening, former Vice President Al Gore was to present Charles with the Global Environmental Citizen Award, given by the Center for Health and the Global Environment at Harvard Medical School. The prince was expected to give a speech.
While Charles has won kudos from environmentalists for his calls to action on global warming, British environmentalists have said the prince should have abstained from flying to the United States. In response, Charles' office said it would cancel a skiing trip to Switzerland, a gesture that would reduce his carbon footprint — the carbon dioxide created by his travels.
Earlier in the weekend, the royal couple visited Philadelphia's Independence Hall, their first trip to the city where Americans declared their independence from British rule.
The royal couple last visited New York in November 2005, when they visited the site of the Sept. 11, 2001, attacks.
The train carriage they used has served several U.S. presidents, Frank Sinatra, British royalty and the body of Sen. Robert F. Kennedy after his assassination.