Ever wonder what your teenage brother and his friends are up to when they’re locked inside their bedrooms all night? Probably surfing the web looking for porn. BUT, they might occasionally get bored of that and put on a performance much like the one Justin Timberlake and Jimmy Fallon did on Late Night with Jimmy Fallon last night. The sequel to their wildly popular "History of Rap" medley from 2010, "History of Rap Part 2" ventured back into the hip-hop vaults, with the guys seamlessly trading back and forth on snippets of Kurtis Blow’s “The Breaks,” Grandmaster Flash and The Furious Five’s “The Message,” N.W.A.’s “Express Yourself,” Public Enemy’s “Bring the Noise,” Rob Base & DJ EZ Rock’s “It Takes Two,” and many more. Expertly backing them was Jimmy’s house band The Roots. It’s stuff like this that makes Late Night the most consistently fresh and innovative late-night show. Sorry, Conan. You’re feeling a little stale.