Davy Rothbart was going about his business one cold February Chicago night in 1999 when he found a handwritten note on his windshield.

"Mario, I [bleeping] hate you," it read.

"You said you had to work then whys your car HERE at HER place? You're a [bleeping] LIAR[.] I hate you I [bleeping] hate you[.] Amber."

Then Amber appended a final line: "p.s. page me later."

So goes the famous story of how Rothbart and a few of his fellow slacker friends created Found magazine, a periodical that collected found notes, funny notes, weird notes, touching and moving notes, creepy notes, and wild notes.

The little zine led to a tour, with Rothbart sharing his finds at bars and clubs across the country, then a podcast and books.

Now you can hear the famous Amber note sung on stage with the latest addition to the Found empire, Found: The Musicalwhich opens Thursday and plays through Dec. 11 at the Philadelphia Theatre Company on Broad Street.

Based on nearly 20 years of found notes, the musical is the brainchild of composer and lyricist Eli Bolin and cowriters Hunter Bell and Lee Overtree. Directed by Overtree, it's coming to Philly after a successful Off-Broadway run in 2014.

Rothbart, 41, said he was amazed to find his friends all had similar finds, after getting the original note.

"Every one of them had a favorite find that they had put up on the fridge," he said in a phone interview from his home in Los Angeles.

Creating a zine seemed a no-brainer, and Rothbart and friends began soliciting finds.

"We asked friends to send us along their finds, and they asked their friends, and word got around," said Rothbart. "So we went to Kinko's at 3 a.m. to put it all together and make 50 copies, and there was this punk-rock teenager behind the counter who said, 'Dude, this is awesome! Let's make 800 copies!' "

So there was Rothbart living with boxes upon boxes of Found the zine.

Things progressed organically from that point, said Rothbart. A launch party helped spread the word and the mag began to sell. It sold so well, he said, "that the neighbors called the police – they thought all these people were coming over to buy drugs."

Rothbart, who has worked as a contributor to the syndicated radio show This American Life, is a natural storyteller. He spoke of "the wild ride" that took him from that Kinko's copy store to a guest appearance on The Late Show with David Letterman and a measure of fame.

The notes, he said, are little windows into people's lives, into their foibles, their troubles. "Some of them are so heartbreaking," he said, "people are just revealing their pain and suffering. To me, the more we read them, the more insight we get into ourselves and our shared humanity."

Our shared humanity? Even the one that reads, "I love you, but I don't know if we can see each other now that we found out we are related"?

Rothbart laughed. "Yes, even that one."

These days, Rothbart is pursuing his passion for filmmaking as a screenwriter and director. His directorial efforts include  Medora, a 2013 documentary about an economically depressed town in rural Indiana on the verge of ruin. The film follows the efforts of a high school basketball team to end their losing streak and restore some pride in their hometown.

Although Rothbart was not directly involved in the musical version of Found, the show clearly captures his fascination with the lives of ordinary people and his slightly ironic and gently comic take on life.

A fictionalized take on the founding of Found, it stars F. Michael Haynie as Davy; Juwan Crawley and Alysha Deslorieux as his best friends and housemates, Mikey D. and Denise; and Erika Henningsen as Davy's gal, Becka. The rest of the 10-member cast play multiple roles.

The narrative loosely follows the creation of the magazine by Davy and his roommates and their national reading tour. It culminates in a dramatic trip to Hollywood. There's comedy, there's romance. There's friendship and betrayal. As each scene unfolds, performers pop in to recite, declaim, shout out, or whisper any one of more than a dozen notes that Found published over the years.

Bell, who cowrote Now. Here. This. and SILENCE! The Musical, said  the challenge with Found was to discover a way to transform the magazine's dizzying array of notes – each containing different characters, ideas, and feelings – into a coherent musical.

"The challenge," he said, "was how to bring the individual notes to life though songs, movement, and speech in various sketches while also trying to find an emotional arc and a way to unify it into a single musical."

Bell says the creative team played around with several storylines before deciding to tell a fictionalized origin story about the real magazine.

"Lynda Barry, the amazing cartoonist, writer, and playwright, has this really incredible word, autobifictionalography," Bell said, "and I really clutched on to that and held that umbrella with this, because we're not doing the documentary … it's inspired by the creation of the real magazine but then autobifictionalographized with original ideas and characters."

Bell said the heart and soul of Found: The Musical isn't the story it tells, but the notes, the finds themselves: "We would take care never to stray too far from the notes or fail to celebrate the notes. That's the heartbeat of the show."

Bell said he sets the bar high. "We really wanted to create the same experience you have when  you open the magazine," he said, "and to fall in love with all these different people and different voices."

Found the Musical

Through Dec. 11 at the Philadelphia Theatre Company, Suzanne Roberts Theatre, 480 S. Broad St.

Tickets: $15-$59 weekdays; $15-$69 Saturdays and Sundays.

Information: 215-985-0420, http://philadelphiatheatrecompany.org/