Justin Timberlake, the Roots and Jimmy Fallon give a rap history lesson

By David Malitz

Justin Timberlake visited "Late Night With Jimmy Fallon" last night and we know he's not one to ever pass on a funny-musical skit sort of thing. So he and Fallon, backed by house band the Roots, ran through a history of hip-hop medley, performing bits and pieces of about a dozen of the genre's most memorable tunes. And also a Soulja Boy song. It was pretty cute. What was the most egregious omission, though?