Paul McCartney wasn't even on stage for the best part of his recent surprise show at New York's Frank Sinatra School for the Arts. After he finished "Hey Jude," the crowd of teens kept singing the "na-na-na-na" ending.

That’s a testament to the power and an endurance of a song that was early into its long run at No. 1 45 years ago this month when many of those students’ parents likely weren’t born. The sing-along also marked the most inspiring moment yet in McCartney’s energetic push for his latest album, “New,” which has him turning up, well, here there and everywhere.

He joked around with Jimmy Fallon Monday. Three days later, he played a surprise set in New York's Times Square, just a couple weeks after packing Hollywood Boulevard during an appearance on “Jimmy Kimmel Live!” The title track from “New” is featured in “Cloudy With A Chance Of Meatballs 2.”

We’re getting the best of the old and something new with McCartney’s promotional campaign and his album, set to officially debut Oct. 15. He’s using social media (Twitter chats with fans, online previews of tracks) and old-fashioned live performances to grab an audience that spans generations.

Those of us lucky enough to catch his Times Square gig (announced via a tweet) joined a crowd that ranged from grade schoolers to grandparents. He played a handful of songs from his latest album, including “New,” which offers echoes of “Got to Get You Into My Life” and “Penny Lane.” He also performed “Queenie Eye,” which sounds like the bouncy niece of “Uncle Albert/Admiral Halsey,” and “Save Us,” which could have sprouted on “Junior’s Farm.”

But the album, shaping up as McCartney’s best since 2005’s brilliant “Chaos and Creation in the Backyard,” is far from a nostalgia trip, spanning styles from ballads to rockers. He’s as still adventurous as ever – and part of that means no longer being reluctant to occasionally tap into the spirit of his early work to produce current hits.

The welcome McCartney barrage comes with the 50th anniversary of the Beatles’ arrival in the U.S. barely four months away. That’s hard to believe – nearly as much so as McCartney’s vibrancy at 71. As he’s shown in his latest spate of appearances, he thrives on performing his music for fans of all ages. “I could be home watching the TV. But I’d rather be here," he told the kids at the Sinatra school.

McCartney’s music, past and present, still resounds, as evidenced the reaction he’s getting from all over. His concert at the Sinatra school is set to be streamed on Yahoo! Monday. In the meantime, check out a clip from his Fallon appearance:

Hester is founding director of the award-winning, multi-media NYCity News Service at the City University of New York Graduate School of Journalism. He is also the author of "Raising a Beatle Baby: How John, Paul, George and Ringo Helped us Come Together as a Family." Follow him on Twitter.