Watch Justin Timberlake and Jimmy Fallon Take On "History of Rap 5"

In the fifth installment of Jimmy Fallon's "History of Rap" (and his first installment as host of the Tonight Show), Fallon closed his first week strong, especially after last night's Michelle Obama kale situation . Along with Justin Timberlake, Fallon tackled some of rap's finest, including Kanye West, The Beastie Boys, and that "hotstepper" guy.