WASHINGTON, DC – Dave Chappelle has built a career on pushing boundaries and challenging social conventions. Rapper and actor Common praised Dave Chappelle's bravery and sociological influence. Musician John Legend paid tribute to Chappelle's passion for music and determination to use his influence to spotlight different artists. At the height of his fame, Chappelle organized "Dave Chappelle's Block Party" — a movie built around an all-star concert featuring Legend, the Roots and a reunion of The Fugees. Chappelle spoke with reverence about the Mark Twain prize and the "art form" of stand-up comedy.