Okay, he's way far out of the Hitfix demo, but he's also cooler than any of us will ever be, so hail, hail Pete Seeger. The legendary folk singer and rebel rouser turns 90 this spring and to celebrate, more than 45 artists are throwing him a garden party-at Madison Square Garden, that is.

On May 3, MSG will host "The Clearwater Concert: Creating the Next Generation of Environmental Leaders," a benefit for the Hudson River Sloop Clearwater, which as founded by Seeger.

Among the artists slated to appear are Bruce Springsteen (obviously. Hello-- "The Seeger Sessions"), Dave Matthews, Eddie Vedder, John Mellencamp, Tom Morello, Steve Earle, Joan Baez, Billy Bragg, Michael Franti, Ben Harper, and many more. We bet there's not a Republican in the bunch!

Seeger led a rousing performance of Woody Guthrie's  "This Land is Your Land" with Springsteen at the "We Are One" inaugural concert in Washington, D.C. on Jan. 18.  

Tickets go on sale on March 23 through American Express, and then to the general public on March 30, according to Billboard.

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