Julia DeVillers wore them at an event at the American Embassy in the country of Georgia. Carolyn Mackler lounged in them on a plane en route to Chicago to attend NCTE. Libba Bray rocked them at band practice. Alan Gratz donned them to chop wood. And Ally Carter sported them on Thanksgiving at her Oklahoma home. What are they? They’re a single pair of comfy pajama jeans (of infomercial fame) that nearly 40 YA authors wore, signed, and passed along during 2011—in the spirit of the protagonists of Ann Brashares’s The Sisterhood of the Traveling Pants.

It all started about a year ago, when Lauren Myracle and David Macinnis Gill began joking about “jeggings” (aka jean leggings) and pajama jeans on Twitter. DeVillers admitted that she actually owned a pair of pajama jeans, and a fellow tweeter suggested she wear them in public, sign them, and pass them on. This lighthearted idea gave birth to “The Twitterhood of the Butt-lifting Pajants,” a project spearheaded by DeVillers and Myracle.

Quite, well—fittingly, Brashares was the final author to wear and sign the Pajants, at an event held December 3 at Books of Wonder in Manhattan. Organized by Pajant wearers Sarah Mlynowski and Courtney Sheinmel, the gathering and book signing rounded up 19 authors who shared tales of their Pajants escapades and greeted fans.

In addition to DeVillers, Gratz, Brashares, Myracle, Gill, Mlynowski, and Sheinmel, the Pajants participants in attendance were Tara Altebrando, Jen Calonita, Susane Colasanti, Dan Ehrenhaft, Elizabeth Eulberg, Adele Griffin, Maureen Johnson, E. Lockhart, Leslie Margolis, Jennifer E. Smith, Melissa Walker, and Robin Wasserman. A highlight of the evening was a slide show prepared by Lockhart (which can be viewed online), showcasing some of the authors in their Pajants glory.

Prom & Prejudice author Elizabeth Eulberg, who wore the Pajants to participate in an author reading at the New York Public Library earlier this year, praises Mlynowski, Sheinmel, and Books of Wonder owner Peter Glassman for pulling off the author- and fan-packed in-store event. “They worked tirelessly, and I was very impressed,” says Eulberg. “As a publicist, I know that trying to get two authors in one place at one time is not easy, but the fact that they were able to get 19 authors to attend is amazing.”

Glassman agrees—though he admits that he was a bit skeptical as the event-planning picked up steam. “When Sarah and Courtney initially approached me, they said they thought there would be about six authors involved,” he recalls. “And then when they said the number was growing, I said, ‘That’s great—the more the merrier.’ Big mistake! When the count reached 18, I had to tell them I couldn’t handle any more than 20, or they’ll have to sit on each other’s laps!”

It all came together in the end, with seats for each author, reports Glassman, who observes that a number of non-Pajants-wearing members of the author community—including David Levithan and Jon Scieszka—turned up for the event. As did teen readers, who, Glassman says, “were thrilled to see so many authors in one place. It was wonderful to see how very excited they were.” Glassman displayed recent and backlist books by the authors who, as an extra bonus for the store, signed back stock for upcoming holiday sales.

Eulberg says that the event—and the entire Twitterhood of the Butt-lifting Pajants project—illuminates the closeness of the YA author clan. “I have been so humbled and moved by how much YA authors support each other, and this has been a true example of that,” she observes. “We all have each other’s backs.”

And the traveling Pajants themselves will also have a happy ending: they’ll be auctioned off in the spring to benefit Reading Is Fundamental. These are very special pants, says Eulberg, noting that they fit all body sizes—from the male authors who wore them to Tyra Banks, who got involved in the Pajants fashion show because she and Adele Griffin have an acquaintance in common. “I think we’d all agree,” says Eulberg speaking for her writing colleagues. “These are definitely magical pants.”