10/17/2012 05:46 pm ET Updated Dec 17, 2012

Russell Crowe at Gramercy Theatre

It's 2 a.m. in New York before the last Russell Crowe fans finally vacate the Gramercy Theatre. Representing a wide variety of states and nations -- Texas, Canada, Israel, Indonesia -- many had been there since 6 p.m., eager to share an evening of songs and stories with the Oscar-winning Aussie and his assembled colleagues. What they got was a night of pure joy.

The Indoor Garden Party saw Russell once more reunited with his Merry Men from 2010's Robin Hood: Scott Grimes (ER, American Dad!), Kevin Durand (Lost, Real Steel), and Alan Doyle (lead singer of iconic Newfoundland band Great Big Sea). Bonded by their stunning artistic talents, an undying love of performance, and the perpetual search for a good time, the foursome has, over a decade of friendship, built one of the most enthusiastically prolific creative communities in recent history.

"It's just a wonderful thing," says Alan, "to get together and sing a few songs. And I'm so happy that we've come to a place, all of us, in our different careers where that's enough."

Enough, apparently, to persuade fellow performers of every stripe to join the fun. Guest artists continually upped the ante on the pleasure scale. Les Miserables ingénue Samantha Barks, making her American debut, charmed the crowd with her soulful voice and insouciant sense of humor. (Appearing barefoot onstage midway through the show, she joked, "The shoes are off, so it's serious business.") Between numbers, Irish duo Size2Shoes drew laughs with their rationale for "sampling" ("We use bits from other songs in our music so you'll think we're famous!") And, at the height of universal excitement, Sting suddenly emerged from the wings for a surprise serenade of "Every Breath You Take." Cue excitement tipping over into cloud-nine ecstasy.

But all roads lead back to the Merry Men. At its core the Indoor Garden Party celebrates their incredible chemistry. Watching each member of the quartet showcase his own unique abilities (you kill that keyboard, Scott Grimes!) and then blend seamlessly into a four-part harmony for a rendition of "Beautiful Girls" is a thrill beyond words.

It's a miracle of, to use Alan's phrase, "circles connecting" that four such seemingly dissimilar men became friends in the first place: "Russell, Kev, and Scotty met while filming a movie in Canada [1998's Mystery, Alaska]. They got on like a house of fire because they're like-minded fellas, and the soundtrack for most of their parties was Great Big Sea." In 2004, Russell and Alan met while presenting at the NHL Awards and decided to start writing songs together. Since then they've released three official albums and countless tracks for movies and other bands.

"I know I've become better at my job since I met all those guys," Alan notes, "because we come from different parts of the earth and our early musical skill sets were so different."

That diverse mélange of elements reflects the guys' "gypsy" philosophy -- an artistic existence based solely on insatiable curiosity about the world and its stories. Alan admits that Russell is "one of the most curious people I know," but he gladly gives him a run for his money: "I always want to see what's around the corner; I always want to meet one more person, sing one more song. Stay up the latest. Get up the earliest. I want to be the guy who lived the most."

Ultimately "living" for Alan comes down to entertaining the audience. "Once eight o'clock comes, I can't help it. The moment the curtain rises, I want everyone in the room to have the greatest night of their lives. I'm lucky that most times people are satisfied to hear me sing. But in truth, unlike most of the greatest artists of our time, I would abandon them all if I thought it wasn't working. My desire to leave everyone panting at the end of the night is too strong."

Panting literally occurred at the Gramercy Theatre, thanks to Size2Shoes including that action in one song and encouraging full participation. "Communal" was the night's keyword, as a bushy-bearded Russell -- fresh off the set of upcoming epic Noah -- engaged the audience in pre-show vocal exercises and Scott's version of "Man in the Mirror" brought all present to shout the chorus. "I want you to take this away when you leave -- you made this show tonight!" the golden-voiced redhead enthused.

If you've read this far, you might be wondering whether the event had any negatives. Only one -- that it had to end. But with Russell as their guide, the boys are always searching for the next adventure. (Alan asserts, "There's nobody in my professional life, anywhere, who's as ready to start work as Russell Crowe.") Thus the fans wait, wrapped in the intoxicating haze of happiness, for the gypsy drums to pound again -- and soon.