SIR PAUL MCCARTNEY, the patron saint of rock ’n’ roll, former Beatles bass player and Wings frontman, performs on the 10th Street meadow in Piedmont Park. The presence of such rock ’n’ roll royalty has been summoned forth to our fair city in honor of Piedmont Park Conservancy’s 20th anniversary. Dubbed the Green Concert, proceeds from the show will contribute to a 40 percent expansion of the park’s 53 acres, yearly upkeep and environmental sustainability. It’s a piece of history with a cause. Irish trio the Script opens the show with a hodgepodge of modern soul, pop and hip-hop tunes. $79.50. 4 p.m. 400 Park Drive. 404-817-8700. www.ticketmaster.com.