Weezer Rock Brooklyn at Williamsburg Waterfront Gig

Two songs into Weezer's performance Friday night at the Williamsburg Waterfront, a Brooklyn, NY, outdoor concert space situated across the East River from Manhattan, singer Rivers Cuomo disappeared into the crowd. Yielding to the cat-like curiosity that would later have him climbing speakers and contemplating a run up the rope ladder used by the light crew, Cuomo had edged onto a ledge on the far side of the stage and jumped into the pit. Now, he needed a boost.

"Someone help me up," Cuomo said meekly, as if he'd just been tripped by the captain of the football team. "I've got to play guitar on this next jam."

Sure enough, his band -- the four instrument-swapping sidemen that make up this, the strangest Weezer lineup yet -- had already started playing the 1994 single 'Undone: The Sweater Song.' Cuomo made it onstage just in time, and for the new few minutes, he sang a song as familiar to 30-something fans as the little girl sitting on her father's shoulders.

"Generation X, Generation Y, Generation Z," Cuomo said afterward, addressing the three age groups that, amazingly enough, have had the chance to grow up on his music. "You want to count on sufficient, adequate Porta-Potty access, and we have provided that for you tonight."

Cuomo was being his usual opaque, half-ironic, purposely dweeby self, but to the extent he was talking about comfort -- the kind that involves not just using reasonably clean toilets, but joining the sweaty, shirtless dude next to you in screaming 'Say It Ain't So' at full volume -- he spoke the truth. The band mostly stuck to singles and beloved album tracks, such as 'Surf Wax USA,' and in that sense, it delivered a straightforward, good-times best-of set -- the type Journey, Fleetwood Mac or any other band with more than two decades' worth of hits might.

Only there's nothing straightforward about today's Weezer. Since regrouping in 2000 after a three-year hiatus, the band has moved away from the dark humor and heavy feelings of its early work, replacing rock-geek power-pop with the hooky, simplistic likes of 'Island in the Sun' and 'Beverly Hills.' Cuomo and company played both Friday, treating them more like arena sing-alongs than the calculated pop experiments -- or even practical jokes -- some disenchanted former fans claim they are.

Then there are the instrument changes: after years behind the drums, Pat Wilson primarily plays electric guitar, which is fortunate, since Cuomo spends about half of his time sans six-string, using his free hands to make hip-hop hand gestures and strike triumphant metal-god poses. Second guitarist Brian Bell switches occasionally to keyboard, as does Scott Shriner, the third bassist in the group's nearly 20-year history. Friday night, Shriner also sang lead on 'Dope Nose,' from 2002's 'Maladroit,' the follow-up to the previous year's self-titled comeback LP, known as 'The Green Album.'

Weezer closed with its mash-up of MGMT's 'Kids' and Lady Gaga's 'Poker Face,' songs it's been covering for some time, but that took on added meaning Friday, given that both are by New York City artists.

After a New Jersey radio-contest winner helped Cuomo sing '(If You're Wondering if I Want You to) I Want You To,' the lead single from last year's 'Raditude,' arguably Weezer's best album in years, the band reached back to the '90s for 'Buddy Holly,' still its signature tune.

When the song was finished, Cuomo, Shriner, and Bell grabbed sticks and descended on newbie drummer Josh Freese's kit. Their amateur-hour 'Stomp' ended the night on an aggressive, patently ridiculous note, the only kind that would have rung true.

Watch the band perform 'Undone: The Sweater Song' at last night's show: