When recounting a moment of inspiration, some compare it to a thunderclap: sudden, startling, stunning. Mad Libs arrived with a guffaw. The series of books--composed of stories that feature blank spaces where readers can fill in their own words--was co-created by Leonard Stern, who died June 7 at age 88. One day in 1953, Stern was writing a television screenplay when he asked humorist and office mate Roger Price for an adjective, not revealing that it would describe a character's nose. Clumsy and naked were the replies. Since the duo's first, self-published set of books that year, Mad Libs has grown to 120 volumes that have sold 150 million copies. Stern, also an award-winning TV director and producer, taught generations about the variety of language and the necessity of humor.