Paul McCartney is adding to his busy summer with top-billing at the Outside Lands Music & Arts Festival, which will take root in San Francisco's sprawling Golden Gate Park from August 9 - 11. For his first time at OSL, the former Beatle will be joined by festival staples Red Hot Chili Peppers, Phoenix, Yeah Yeah Yeahs and a resurgent Nine Inch Nails, among many others.