Full of cameos:
http://www.youtube.com/watch?v=1e0EQlQXoEoI first heard this song done by the Blind Boys of Alabama. Now I can't say which one is my favorite.
Here's the list of who's in it (got this from stereogum.com who says they're bullshitting on one name):
Iggy Pop
Kanye West
Chris Martin
Kris Kristofferson
Patti Smith
Terrence Howard
Flea
Q-Tip
Adam Levine
Chris Rock
Justin Timberlake
Kate Moss
Sir Peter Blake
Sheryl Crow
Dennis Hopper
Woody Harrelson
Amy Lee
Tommy Lee
Dixie Chicks
Mick Jones
Sharon Stone
Bono
Shelby Lynne
Anthony Kiedis
Travis Barker
Lisa Marie Presley
Kid Rock
Jay Z
Keith Richards
Billy Gibbons
Corinne Bailey Rae
Johnny Depp
Brandon Flowers
Graham Nash
Brian Wilson
Rick Rubin
Owen Wilson