“We’re here celebrating an album that was released nineteen years ago, which is a weird anniversary, I guess. But we recorded it twenty years ago, so…”

Peter Bjorn and John’s frontman Peter Morén’s signature dry humor rings over the crowd in Manhattan’s iconic Irving Plaza, describing the purpose of their current tour: to play their debut album Writer’s Block in full. Nineteen years is an odd number to celebrate, but odd in a fitting way. Peter Bjorn and John have always had an off-kilterness to them, a sort of droll presence that preceded the Brooklyn hipster movement they almost certainly inspired.

Perhaps at one point, a theatre in Williamsburg may have been a more appropriate venue, but nineteen years after the success of folk-pop hit “Young Folks,” the more storied halls of Irving Plaza feel more apt. Fans this time around seem to have brought their own young folk, with a fair amount of parents introducing their children to what I’m sure they’re referring to as “proper music.” A fan waves a sign that says “I got married to this song!” There’s a larger feeling of history to the show, like the crowd is not just there to enjoy the songs but also to sit with the memories and stories that happened to those songs. It’s heavily nostalgic, but not in a way that feels too heavy or overbearing. It’s not a high school reunion, but it is a homecoming of sorts.

Fans are decked in merch that dryly reads PETER BJORN AND JOHN TSHIRT or PETER BJORN AND JOHN TOTE, matching with the band’s own PETER BJORN AND JOHN BASS DRUM. It’s the same quirky sort of humor that reminds people of the early days of The Office, but again, doesn’t feel cheap or cringy.

Taking “looking back” almost literally, they played through the entirety of 2006’s Writer’s Block in reverse, starting with last song “Poor Cow” and ending with the intro “Objects of My Affection.” It’s just another slight twist on the night that sums up the band: celebrating the 19th anniversary over the 20th, stagehands in matching PETER BJORN AND JOHN TSHIRTs, lighting that is both dark and brightly strobing, an album played in reverse.

It’s a tribute not just to an iconic album and band, but to an entire ethos of witticism and humor that saw the band’s rise to success in the first place. And judging by the amount of children in the crowd, watching in rapt attention, that legacy is far from over.