Music festivals are fairly commonplace in the City, but few combine titanic star power with social change. The annual Global Citizen Festival tackles that effort, bringing together some of music's biggest stars—Beyoncé, Ed Sheeran, Pearl Jam and many more are on this year's bill—to raise awareness around the fight against poverty, hunger and climate change throughout the world. Curated by Chris Martin, whose band Coldplay will also appear, the show is a day of free music in Central Park’s lovely Great Lawn. But getting tickets requires taking action, from signing a petition to help empower women and girls to tweeting about clean water in underdeveloped countries. A select number of tickets will be granted to those who take the most initiative and participate in the largest number of efforts. For more information, visit globalcitizen.org.