It seems like only yesterday that the world was introduced Peter Bjorn and John and their ubiquitous hit 'Young Folks.' As the Swedish popsters pointed out throughout their set Thursday night at Chicago's Metro, they just turned double digits, having formed in November of 1999. There wasn't any cake, per se, but the vibe was clearly celebratory. Much to the delight of singer-guitarist Peter Morén, a group in the crowd broke into the Swedish version of 'Happy Birthday.' The band also brought two people onstage who were also celebrating birthdays to jam with them -- on bongos and guitar -- for 'Young Folks' and 'Needles and Pills.'

Perhaps the biggest surprise, though, was just how energetic the whole night was, especially considering that the band's recent effort, 'Living Thing,' is an incredibly minimal, almost sleepy LP -- more rainy-day bedroom pop than something ready for the dance floor. Before the trio hit the stage, some kids were thrown out by security and an audience member said, sarcastically, "Wow, Peter Bjorn and John really bring out a rowdy crowd." That was a joke, but based on people's reactions to each song it wasn't that much of a stretch. 'Living Thing''s ELO-nodding title track, '4 Out of 5' and 'Nothing to Worry About' (complete with a rapper who jumped onstage to freestyle) were much more lively in person.

The energy can be attributed to PB&J's sheer goofiness as much as anything else. When the band walked onstage, a giant backdrop fell behind them with the word 'backdrop' repeated over and over on it, eliciting laughs. Morén skittered across the stage during a guitar solo, then spat water on the audience with a punk bravado. Later, he did his best Tom Jones, loosening his tie, throwing it over his shoulder and mockingly acting out his lyrics. They also played the excellent 2002 cut 'People They Know' for the first time in Chicago, giving the audience a glance into the band's power pop beginnings.

Here's to new beginnings for PB&J and another 10 years of 'Living' it up.