AT 7:05 P.M., I arrive at Sarah Grey's house for "Friday Night Meatballs." Considering that I'm sort of crashing this dinner party at her Fishtown home, I'm self-conscious about being the first guest in the door.

The feeling worsens when I realize I've stupidly forgotten to bring something to contribute to the night's meal. I offer my hostess neither wine, dessert nor humble daisies for the table.

I feel my smile freeze on my face. I am mortified.

But the ever-chipper Grey, 35, is too chilled-out to notice (or at least to comment on) my empty hands. Instead, she pours me a glass of something red and introduces me to her sweet husband, Joe Cleffie, 48, and their adorable, crayoning kid, Lucia, 6, who is sprawled on the living-room floor amid a clutter of paper.

Soon, Grey's cheer, Cleffie's banter, Lucia's artwork, and the savory aroma of stewing meatballs have me kicking back on the sofa like I've been here a hundred times before. By the time the other guests arrive, I'm feeling so at home, I think, "These people really have this meatball thing down cold. No wonder it's gone viral."

If you've never heard of "Friday Night Meatballs," you've probably never read the food blog "Serious Eats."

In August 2014, Grey wrote a piece for "Serious Eats" about the meatball dinners that she and Cleffie host every Friday (barring illness or vacations) in their York Street rowhouse. Titled "Friday Night Meatballs: How to Change Your Life With Pasta," it was shared tens of thousands of times. The piece has inspired readers from across the country and around the globe - including folks in India, Latin America, Ukraine, Gaza, Vietnam, and Argentina - to host their own weekly, communal meals.

"People really love the idea," says Grey, who has created a hashtag - #fridaynightmeatballs - so Instagram and Twitter users can share photos of their gatherings. The cult widens every time Grey is interviewed on another podcast (like "The Plural of You") or for another magazine (Real Simple). "It has touched on something we've all been missing."

Grey didn't set out to be the meatball lady when she dreamed up "Friday Night Meatballs" in November 2013. She was simply craving connection, the face-to-face kind that's been slowly replaced by social media.

Grey works from home as an in-demand freelance editor of history and political-science books. Cleffie is an equally busy office manager for a South Philly security company. When they became parents, they had scant time to socialize (and not much money for a sitter, anyway).

"It was very isolating," says Grey, a self-described "hardcore extrovert." She and Cleffie don't have kin in the area, so they can't pop in on family for the kind of easy, relaxed dinners that Joe, especially, had enjoyed as a child - the kind that bring folks together, without fuss, to eat un-fussy food.

So on her 33rd birthday, Grey used Facebook to announce that she and Cleffie were going to make their lives happier by starting a new tradition called "Friday Night Meatballs."

"We're cooking up a pot of spaghetti and meatballs every Friday night and sitting down at the dining-room table as a family, along with anyone else who'd like to join us," she wrote. "Friends, neighbors, relatives, clients, Facebook friends who'd like to hang out in real life, travelers passing through: You are all welcome at our table. We'll just ask folks to let us know by Thursday night so we can know how many meatballs to make.

"You might make new friends," she hinted. "We'll just have to find out. This is our little experiment to spend more time with our village. You're invited."

The response was crazy and instantaneous - tons of likes, comments, and invite acceptances.

Said Cleffie, "We're going to need more chairs."

It took a few weeks, but "Friday Night Meatballs" settled into an easy routine as Grey and Cleffie got more efficient at prep work, worried less about cleaning their cluttered home beforehand, and capped attendance at 10 adults ("and as many children as can play well together without too much supervision," says Grey).

"Friday Night Meatballs," instead of becoming something to stress about became instead a comforting and convivial way to cap off the week. While leisurely consuming delicious, simple fare (made by Cleffie, who has perfected his grandma's meatball recipe) around a table glowing with candlelight, the talk flows in ways not possible with text messages or Instagram posts.

"It's never been awkward," says Grey, even when attendees have been strangers to them, as was the case when an out-of-town friend asked if a relative visiting Philly could attend the dinner.

"There's nothing like a meal to bring people together. By the time we get everything on the table the night evolves on is own."

As guests from the couple's many work, social, and familial spheres mingle, the conversation can get surprisingly deep and far-ranging.

One of Grey's friends, a medieval-literature professor, once led a rousing discussion relating the Lord of the Rings movies to Beowulf. And heated political debates are not uncommon.

"But I don't want it to sound more high-minded than it is," says Grey. "We can just as easily get into fart jokes and discussion about when a mom should start feeding her baby solid foods. I love that we can never predict what the conversations will be. The only rule we have is no racist stuff and no hate."

The time I spend at "Friday Night Meatballs" is delightful.

I meet Stephanie Lee Jackson, a funny, brilliant artist and holistic body-worker whose daughter is best friends with Lucia; the girls flit in and out of the dining room like Tinkerbells as we dig into our second platefuls of spaghetti. And I am charmed by Sofia Arias, an NYU grad student and Facebook acquaintance of Grey's. She's in Philly for a Saturday conference but has come a day early, for "Friday Night Meatballs."

Over dinner, I can feel their acquaintanceship growing into a friendship. It's lovely to see.

" 'Friday Night Meatballs' has changed our lives," says Grey. "The isolation is gone. We have a real feeling of community. We're so happy these days."

All thanks to meatballs.

215-854-2217 @RonniePhilly