I certainly did not expect Tom Morello from Rage Against the Machine to show up at Bruce's concert. But he did--played The Ghost of Tom Joad with the Boss--and I've got to say--his guitar work BLEW me away. Remind me to go to the next RATM concert. He's fucking incredible. (Yeah, I know I sound like a teenage boy. . .)
Here's a link to a bootleg You Tube video of the song. Unfortunately, it cannot do justice either to the sound or the visuals of the performance. Still worth a gander, though.