Mary J., Kweli and Others Appear on "30 Rock"

30 Rock "Milton Green" Song from On221 on Vimeo.

Last night's season finale of "30 Rock" featured a star-studded lineup of performers -- Mary J. Blige, Adam Levine, Wyclef Jean, Talib Kweli, The Beastie Boys and others -- on a "We Are the World"-esque charity song.