On Oct. 9, around 2,500 strangers packed Montreal's Place des Arts concert hall to sing Leonard Cohen's "Hallelujah" in surprisingly perfect harmony. The melody was beautiful. In a video recording posted online, tears and smiles are visible as people sing out the familiar chorus. You could say it was a spiritual performance—unless you're Nobu Adilman, who co-organized the event, for whom this mass choir has always been about enjoying life. While people often feel tapped into a higher power, Adilman is more pragmatic about the whole thing.

Adilman, along with his artistic partner, Daveed Goldman, founded the group Choir! Choir! Choir! in a living room more than a decade ago. The idea was simple: strangers singing songs together. Those first contributors had so much fun, Adilman and Goldman decided to keep it going. The group grew in popularity until they amassed hundreds of thousands of social media followers and tour dates that rack up hundreds, even thousands of paying attendees.

And before all that, Adilman worked at CBC with a young Ralph Benmergui. Adilman reconnects with his old mentor on Not That Kind of Rabbi to discuss the origins of his hit group and the innate spirituality of music.