Grammy Awards: Dylan, Mumford & Sons and the Avett Brothers bring an acoustic fury

Some classic instrumentation can go a long way, and Mumford & Sons have been a steady-building success story, but the act's run-through of "The Cave" should add some acceleration. The lyrics are mysterious, and the imagery is more foreboding than anything Eminem will cook up tonight, as the band brings plenty of tension to its acoustic works.

The Avett Brothers' "Head Full of Doubt, Road Full of Promise" started slower, but gradually built, and by the time the band starts singing that "darkness" is taking over, the mood and tone of the music reflects it. The moment that everyone was waiting for, however, was the arrival of Bob Dylan, making one of his rare Grammy appearances. He saing "Maggie's Farm," with all of the Avetts and Mumfords backing him. The mike was wobbly at first, but Dylan's voice is wobbly, so it doesn't really matter. It's a song of personal revolution, and standing up to an unjust employer, so it worked well for these recessionary times.