Of course, not everybody has gotten the memo. Take Donald Trump, who has contributed his name to a foundation but little more. An investigation by The Smoking Gun Web site described him as possibly “the least charitable billionaire in the United States,” for he apparently gave the foundation just $3.7 million — over 20 years. Trump, who has said he is worth $7 billion, is not even the largest contributor to his own foundation.

(A spokesman for Trump suggested that it would be “totally incorrect” to characterize him as uncharitable, saying that he has also donated land in upstate New York for public parks and “millions of dollars” to other causes.)

Turner isn’t shy about encouraging others to jump on board. When I asked if he had any advice for my readers, he grew particularly animated: “You don’t have to have any money to make a difference; you can pick up trash walking down the street, and I do that all the time,” he said. “You can volunteer your time. You can be a big brother or a big sister.”