Joke File: Bob Hope and American Variety (Library of Congress). Bob Hope and American Variety: Joke File. To comedians, "material" -- their jokes and stories -- has always been precious, worthy of protecting and preserving. On stage, a good vaudeville routine could last years as it was performed on tour across the country. In radio, a year's vaudeville material might be fodder for one week's broadcast. Bob Hope used new material not only for his weekly radio series, but also for the several live charity appearances he made each week. In the beginni