A guitar pull or, less folksy and more to the point, a song swap involves a handful of musicians taking turns playing tunes and often sharing the stories behind them. (It’s said that the late, great Roger Miller figured the term “guitar pull” originated from there typically being only one guitar to be shared when struggling songwriters got together, and the singers would have to “pull” the guitar away from one another.) This format is the bread and butter of Nashville’s artist-jumpstarting Bluebird Café, and perhaps the most well-known of these gatherings, the In Their Own Words series at Greenwich Village’s Bottom Line, even inspired two compilations on the Razor & Tie label.

But ever since Jeff Hart pulled the plug in the mid-’90s on his monthly Songwriters Alliance sit-downs–a series that saw artists such as Chris Stamey and Ryan Adams join Hart to trade songs and talk shop–this type of musical get-together has been a little hard to come by in the Triangle. The bittersweetly raucous two-night stand that closed out the Pine Hill Farms house concert series a few years back brought together the likes of Bobby Bare Jr., Patterson Hood and locals Tift Merritt and Kenny Roby. But not much else comes close.

That’s part of the reason that when, one night early last January, Caitlin Cary, Kevn Kinney and Jason Isbell took to The Pour House stage under the name Tres Tangled Truckers, it felt as if something extra special was afoot. The three (on buspeople’s holidays from Tres Chicas, the Sun Tangled Angel Revival and the Drive-By Truckers respectively) had never played together, but you never would have guessed it. When Kinney capped that first trip with “Midwestern Blues,” four guitars (Gib Droll and local hero Dave Bartholomew provided extra support throughout the evening) and Cary’s violin fell in line like friends from the old neighborhood to drive the chorus. Later, Cary sneak-previewed a couple of songs from her duet record with Thad Cockrell, while Isbell rolled out a song he’d finished that day, a birth so recent that the thing wasn’t even named yet. And serving as a centerpiece was a monumental version of “Broken Hearts and Auto Parts” from Kinney, complete with a lengthy, Springsteenish monologue that was as hilarious as it was disarmingly poignant.

“It really felt great up there that night,” recalls Cary. “None of us had known what to expect, really, and so the fact that we all felt compelled to join in on our instruments and with our voices sort of took us all aback, I think. It was just plain fun.” Several times, the three principals joked about getting a minivan and taking the show on the road, even though it was scheduled as a one-off. So sky high was the spirit of goodwill and good music on that night, there’s no doubt that the crowd would have ponied up for gas money, if not the three-month/3,000-mile warranty.

“I have to say that song swapping shows are some of my favorite to do; it’s inspiring as a performer to listen closely to other people while in the ‘out of body’ mode that you’re in when you’re performing yourself,” Cary offers. “I always feel receptive to what I’m hearing, and I’ve never done one of these that didn’t leave me feeling as though I’d really gained something valuable.”

Kinney has similar feelings about sharing the stage. “For me, I do it as kind of a seminar. What people in the real world would do to learn new things,” he says with a laugh. “The thing with musicians, you don’t get to see each other much. It’s hard for me to see the Truckers play or see Caitlin play on a Friday or Saturday, because I’m playing every Friday and Saturday.”

Cary, Isbell and Kinney will reconvene at The Pour House this Sunday, nearly a year after that inaugural meeting, and spirits are already running high. “I’m not sure whether we’ll plan this upcoming evening out more,” says Cary. “I tend to think probably not, and I’m sort of glad for that. Around the holidays it’s always nice to get a surprise.”

Tres Tangled Truckers play The Pour House on Sunday, Dec. 18. Music starts at 7 p.m., and tickets are $12 in advance, $15 at the door. And you can catch Caitlin Cary playing the night before with Tres Chicas at the ArtsCenter in Carrboro for a benefit for the Chapel Hill-based nonprofit organization Ipas.