"Late Night with Jimmy Fallon" has established itself as the best late-night show for musicians to perform, probably because of the pedigree of the show's house band, The Roots (who often join the musical guests on stage). Last night, My Morning Jacket stopped by in support of their new album Circuital, which has been garnering positive reviews. Below is a web-exclusive performance of Circuital's "You Wanna Freak Out." It is entertaining enough for the first couple of minutes, but the highlight comes about three-quarters into the song, when bandleader Jim James lets out a truly filthy guitar riff that puts an exclamation point onto the performance.