Bruce Springsteen is notorious for rocking during his shows until he literally can't go anymore -- to the point where he's occasionally collapsed and needed oxygen. He isn't as young as he used to be, but if the final concert of his recent two-night Pittsburgh stand alongside his friends in Joe Grushecky and the Houserockers is any indication, we don't expect to see Bruce slowing down anytime soon.

In fact, Springsteen left Pittsburgh with an epic three-and-a-half-hour set, treating fans to a once-in-a-lifetime blend of hits, classic tracks, and performances by his friends Grushecky and the Houserockers -- 32 songs in all. 

It was clearly a special show for Springsteen, who told the audience early on, "People have flown to Pittsburgh from all across the world! That's almost as crazy as flying to Asbury Park! It's insane! People come from perfectly wonderful places, and they leave them! I met some people from Sweden, and Spain's here too. Even Italy. It's crazy, and the obligation weighs very heavy on my head."

He went on to prove it with the music, jumping into the crowd repeatedly, mixing up the set list with abandon, and taking obvious joy from an impromptu duet on "Brown Eyed Girl" with a drunken fan. Thanks to a request from Grushecky, Springsteen even managed a concert first. "I've never done this on the guitar before," he told the audience before performing a remarkable version of "Incident on 57th Street":

Watch Bruce Springsteen Perform 'Incident on 57th Street' in Pittsburgh

It was just that kind of night -- for Springsteen, for the crowd, and perhaps most of all for Grushecky, a longtime Springsteen associate and cult favorite who currently works as a teacher in Pittsburgh, and was more than likely playing for a few students who had no idea how cool he really was.

The Boss was clearly in a reflective mood on Friday, reaching way back to his 1973 debut for a performance of 'Does This Bus Stop at 82nd Street?,' then flashing all the way forward to 2009's 'Working on a Dream' album to pull out 'Surprise Surprise.' "In my dreams I've written many, many songs and they sound like the greatest songs every written," he explained to the crowd. "I wake up, write some of these things down, and the next morning, almost invariably, these songs are total s---. In my dream I'd go, 'This is the one that will make them forget 'Born To Run!' Then it's horrendous. This the one song that I wrote in my dreams and was actually good."

The E Street Band is clearly at a crossroads as 2011 draws to a close, but as Springsteen's recent performances have proven, he hasn't lost touch with the music that's always driven him. Whatever happens next, it'll come from the heart.