By Jared D. Childress | OBSERVER Staff Writer - The second annual Blue Note Jazz Festival in Napa Valley celebrated hip-hop's 50th anniversary and drew a diverse crowd of about 24,000 to pay homage to two of the most influential musical genres to emerge in the 20th century, with performances from Mary J. Blige, Nas, Chance the Rapper and artist-in-residence Robert Glasper among others.