Congratulations to Book & Stage’s first graduates, Foster the People. The indie-popsters have progressed from moderately attended free shows in the Cosmo’s lounge to the next stage of their careers, performing for a sold-out crowd at the hotel’s larger Boulevard Pool venue.

A sea of rolled skinny jeans, plunging V-necks and “pumped up kicks” packed the pool deck for Foster the People’s final North American tour stop. Now with a huge radio hit (“Pumped Up Kicks”) and a more established fanbase, nothing about FTP’s performance felt reminiscent of this past spring’s mild four-day Vegas residency. The trio seemed far more confident, showing off a tighter sound and a noticeable increase in overall production.

Credit for the improvement shouldn’t fall solely on the band. As frontman Mark Foster, bassist Cubbie Fink and percussionist Mark Pontius played through most of freshman album Torches, the crowd showed off its lyrical knowledge and enthusiasm for deeper cuts such as “Helena Beat” and “Call It What You Want,” singing along word-for-word and adding to the mood.

Foster, who took ownership of the stage with his unique and versatile pipes, also took a few moments out to fill fans in on FTP’s mission. “To us music is cool, but helping people is cooler,” he said. The band toured from coast to coast in its “Do Good Bus,” lending a hand in each city along the route. In Las Vegas last week, the trio helped out at Tonopah Community Garden and the Las Vegas Rescue Mission homeless shelter.

Of course, Foster the People capped the night with “Pumped Up Kicks,” a perfect way to close out the summer concert series at one of Las Vegas’ best outdoor music venues.