‘Summer of Soul’ First Trailer: Questlove’s Documentary Rediscovers a Joyous Moment in Black Music Questlove is giving music lovers a special treat with the release of his new documentary, “Summer of Soul.” The documentary won the Sundance Film Festival’s grand jury prize and the audience award in the documentary categories.  The documentary features rare footage of the 1969 Harlem Cultural Festival, which went on for six weeks at Mount Morris Park, now Marcus Garvey Park, with performers such as Stevie Wonder, Gladys Knight, and Sly and the Family Stone.  The festival took place two weeks later and 100 miles from the more famous festival, Woodstock. “Summer of Soul” will be released to theaters and on Hulu on July 2nd.  What is the best documentary you’ve recently seen?