Coming up on Saturday, May 24 is the 15th annual Radio 92.9 Earthfest, Boston's largest free radio station concert. Headlining this year's main stage concert is popular alternative rock band Cake. In addition to musical performances, Earthfest will feature family friendly activities and booths with educational displays, exhibits, and food and product samples. Previous Earthfests have drawn more than 100,000 people. Read more.