October 1, 2010 5:20 pm Jimmy Fallon Explains Evolution Of “A History of Rap” Jimmy Fallon talks about his viral hit from “Late Night with Jimmy Fallon” in which he and Justin Timberlake rap to some of the greatest hip-hop songs in history! Whose idea was it? US & World Videos 1:36 Arizona Senate repeals 1864 abortion ban 1:40 Democrats say Big Oil misled public for decades about climate change 1:45 NYPD enters Columbia University in riot gear to clear protest 4:28 ‘Apples Never Fall' and ‘Jurassic Park' star Sam Neill reveals his real name 3:21 Katy Perry's surprising regret about cheeseburger Met Gala look