Jimmy Fallon has been on an absolute roll lately, and he continued his hot streak last night with a crazy performance of Rob Base and DJ EZ Rock's "It Takes Two" with the help of an iPad app and Will Smith. Basically, Fallon and Smith laid the beat down in layers using the app, and then once they had it perfect, they broke into the performance of the song, which they eventually took to the show's stage where The Roots and the crowd got involved.