MADELEINE AND HER TWO FRIENDS had barely pulled up to the bar when one of them began chatting with a cute guy — “in his 30s,” Madeleine remembers. They were on a girls’ weekend at the beach and looking forward to some sun and fun. A few hours and some drinks later, the girls piled into the guy’s car and headed back to their condo. “We are going skinny-dipping!” one of them yelled.

The next morning, there were no regrets. “We had a blast,” Madeleine says. Sure, maybe it wasn’t the smartest move to get into a stranger’s car, “but there were three of us, and, I mean, we had our cellphones.”

Madeleine and her friends may sound like teenagers on spring break, and indeed that’s what they often feel like. But they met decades ago — they were “ice-skating moms” to daughters on the competitive circuit — and are now in their late 50s, divorced mothers of grown children and having, in many ways, the time of their lives. “You’ll be out at a bar and see some guys you think are cute,” says Madeleine. “Until you realize they’re in their 20s. But you forget! You forget how old you are!” (Madeleine, like other singles in this story, didn’t want to include her full name when talking about her sex life.)

There are nearly 80 million Americans who came of age in the revolutionary free love ’60s and ’70s, when rebelling against your parents’ conservative views of adolescence, premarital sex, and drugs was just something you did. About a third of these erstwhile crazy kids are now single — divorced, widowed, or never married in the first place — and while the drugs and rock ’n’ roll of their past may have stayed there, to hear this group tell it, sex and desire certainly did not. Match.com reports that 50-plus is the site’s fastest-growing demographic. And according to a survey on its sister site for older daters, OurTime.com, 87 percent of 50- to 70-year-old single users say that physical attraction is a “must have” for a potential partner.