Pete Seeger only turns 90 once, so why not have a big party? True to the folk singer's activist legacy, this packed Madison Square Garden celebration was a fundraiser for the Clearwater sloop and sailboat-centered foundation that Seeger built in 1969 to raise awareness about a then-near-dead Hudson River.

Of course there are still sailing tours of the river to give, so Seeger had some of his friends stop by to help raise some money. Billed as "over 40 artists representing a wide variety of musical genres and generations," the actual number of performers seemed upwards of 60 and included old friends like Joan Baez and Arlo Guthrie, and newer ones like Bruce Springsteen and Dave Matthews. Though billed, Eddie Vedder and Juanes were no-shows. Perhaps filling their spots, Sesame Street's Oscar the Grouch stopped by to sing about trash.

The night's highlights included Joan Baez, who sounded like a regal queen, with a voice undiminished after all these years, and actress Ruby Dee, who rendered MSG silent as she movingly read the Seeger poem "The Torn Flag" accompanied by banjo player Bela Fleck. The night's main attraction (besides the birthday boy), Bruce Springsteen is a man used to playing the big rooms and can truly tell a story. Before playing "The Ghost of Tom Joad," he spent few minutes talking about his and Pete's trip to Washington, DC to play the inauguration and at one point got a roar out of the audience when he said: "Pete, you outlasted the bastards, man."

In addition to Seeger, the night was also about family. Ben Harper played with his mother and aunt. The McGarrigle sisters sounded piercingly shrill and looked a little scary in several appearances, but the rakish Rufus Wainwright had older audience members asking each other who the man with that voice was. Actor Tim Robbins and his son Miles joined the McGarrigle family for "Michael Row the Boat Ashore." Seeger's grandson Tao has accompanied grandpa for years, so of course he was there, and many other family members, including older brother John, who is 95.

But after a four-hour game of revolving door performers, one thing is clear: the show could have been shorter. Ramblin' Jack Elliott seemed particularly lost with Arlo Guthrie, Steve Earle and others on "Mary Don't You Weep." Kris Kristofferson and Ani DiFranco is did an oddly uncompelling and plodding version of "Hole In The Bucket." Sometimes these secondary-artist configurations seemed a little too off-the-cuff.

Of course the night officially ended with all the performers onstage and the entire audience singing "This Land is your Land," and then Joan Baez led everyone in "Happy Birthday." Happy birthday, indeed. Watching Seeger up there leading the crowd in singalongs all night, it's obvious that his lifelong activism carries over onto the stage: Seeger gets everyone involved and inspired, so when he asks you to sing you better sing. It would absurd not to.