If you're wondering where the fit and self-made rich men hang out, the New Yorker has a good tip about where you can find some of them.

They say that marathon training attracts a lot of wealthy type-A personalities. They note that the average participant in the ING New York City Marathon has an annual household income of $130,000.

The people who read Runner’s World have a median income virtually the same as that of the readers of Forbes. When I talked to Cliff Bosley, the director of the Bolder Boulder, one of the largest road races in America, he said, “Running has demographics that are comparable to golf.”

Charity has become a major part of marathons, as runners claim limited entry spots by raising money for worthy causes. Mary Wittenberg, the president of the New York Road Runners, the nonprofit that organizes the city’s marathon, told me that participants tend to be type-A overachievers who are attractive to advertisers. “Why are ING and the Bank of America involved?” she said, referring to the title sponsors of the races in New York and Chicago. “You want a customer that’s in it for the long run, somebody who is going to look to retirement. That’s a goal-oriented, driven person. It’s all about the quest.”

The photo above is by Derek7272

Jennifer Lopez, age 39, is in intensive training to compete in her first triathlon in September. She decided she would train for a triathlon while she was pregnant. Now, only seven months after giving birth to twins, she'll be finishing her first triathlon. See her doing the bicycle part of her training in the video below. The very fit woman interviewing her is chief editor at Self magazine, and she is also training for the same triathlon, but in her case it's not her first one, it sounds like she's already got a few behind her.