The 1970’s are over, but some things are making a comeback: lava lamps, wallpaper, Donna Summer’s concert tour and… swingers.

“The lifestyle” (as swingers fondly call it) is seeping into suburban, upper-middle class social scenes, and people are taking notice. Over drinks and dessert, discussions, once focused on home renovations and restaurant openings, are now giving way to talk about wife-swapping and tales of key parties down the block.

Last month, I attended an end-of-the-elementary-school-year family barbecue in my woodsy suburban neighborhood outside of Washington, D.C.

Sitting with four other couples as the kids played Wii downstairs, the parents’ conversations turned from second grade teacher reputations and fourth quarter grades to the rumored “swingers” parties one community over. Those of us who had heard it before had a twinkle in their eyes.

It shocked those who hadn’t — then sparked their curiosity.

Is this curiosity a throwback to the free-feeling ’70s or are 30-and-40-something married couples getting restless?