It started out as another show at Irving Plaza. Maroon 5 was on stage and lead singer Adam Levine belted out "Not Coming Home" as stragglers like myself raced up the stairs to the stage. The crowd was packed tight enough to be a fire hazard, the drinks were overpriced but the vibe was pure rock and roll.

The band breezed through favorites like "The Sun" and "Shiver" and the audience bounced to the familiar beats. The always smooth "Sunday Morning" brought memories of lazy, naked weekends to surely more than one attendee who was pleased to hear most of their favorite songs early in the show.

Then just when most of us were ready to hit the bar for another drink, Adam started saying something about a guitarist that was going to come out and give the band a hand. I turned and thought better of another vodka tonic.

"I think this guy is going to make to make it in this business," Adam yelled sarcastically. "Please welcome John Mayer!"

And the room exploded with a sonic boom of cheers and applause, all rolled into one mass sound.

Mayer played "This Love" and "Tangled" with the band, displaying a raw, unbridled form of guitar-playing that was akin to watching guitar greats from the past. Perhaps this is how the man truly plays his instrument when he lets loose and pretends he is Stevie Ray Vaughn, his head cocked back and his face contorted from the ecstasy brought on by his six-stringed mistress. During the 10 minutes Mayer shared the stage, the cheering never stopped. It felt about 20 degrees hotter as we watched the band and Mayer play off one another. It was like watching a couple of giddy teenagers jam in their parents' basement, and do so exceptionally well.

Choosing not to steal the band's thunder, Mayer disappeared into the night and let the crowd catch their breath while Levine belted out "Secret" and "She Will Be Loved."

Adam also gave the crowd a preview of some new material with their new song, "Wasted Years." He left us with a rendition of Nine Inch Nails' "Closer," which, judging from some people on the floor, inspired several couples to go home and fuck like animals.

The second biggest surprise of the evening, next to the cameo appearance by Mayer, was when drummer Ryan Dusick took over the mic during the encore and closed the show with a raucous version of "Highway to Hell." Long-time Maroon 5 fans will say that they never knew he had it in him, while newbies like myself were impressed by seeing two sets of such strong vocals in an amazing new band.