When Ron Riedel’s kids graduated from high school, he and his wife, Lorita, found they were socializing less. They weren’t meeting up with friends at soccer games, school plays and other kid-related events.

So Riedel formed a “Baby Boomer” group through his church that hosts regular game nights and weekly dinners.

“When our kids were around, we had reasons to get together,” said Riedel, 55, of Auburn, Calif. Now, “we had less excuses to get together, so we invented this.”

The group plays everything from lawn games to Connect Four. “It has nothing to do with the games,” he said. “It’s really just a social event.”

As baby boomers age, many of the traditional ways to make friends disappear, said Lynda J. Sperazza of the State University of New York at Brockport, who studies how this generation spends its free time. Many start looking for new social outlets. “Game nights and boomer clubs are a means to be active, which is in sync to their values,” she said.

The U.S. Census Bureau defines baby boomers as people born between 1946 and 1964.

Games and the social interaction help people stay mentally sharp, said Dr. Martha Stearn of the St. John’s Institute for Cognitive Health in Jackson, Wyo. “We are programmed to be social. Isolation is one of the worst things for the brain,” she says.

Judy Palladino, 57, a player in a mah-jongg group in Mayfield Village, Ohio, said she and her husband, Vince, like the excuse to get together with their friends. “It’s also important to stay active,” Palladino said.