Last fall, when Justin Timberlake was promoting The Social Network, he and Jimmy Fallon performed a rousing history of rap medley that touched upon a lot of hip-hop’s most important and influential songs (backed by the Roots, of course). So now that Timberlake is making the late-night rounds again to plug Friends With Benefits, he and Fallon performed a follow-up (video below).

This version is… not as good. Fallon and Timberlake goofily give it their all — the dance to Salt N’ Pepa’s “Push It” is a nice touch — but this medley feels like a collection of all the songs that weren’t good enough to include in the first performance. This isn’t so much “A History of Rap Part 2″ as it is “A History of Club Hits.” Seriously, the only time Nelly should be included in A History of Rap is the chapter on crappy rappers. You’ll see him pictured next to Ja Rule and Drake.

Anyway, enjoy this now — the online music rights will expire in the next couple days.