4 to 10 p.m. Waikiki Shell, O’ahu

 This annual two-day concert will feature a variety of performers including Jack Johnson. Doors open at 2:30 p.m. Cost ranges from $40 to $125. All proceeds benefit the Kokua Hawai’i Foundation, a nonprofit that supports environmental education programs in Hawai’i. www.kokuafestival.com, www.myspace.com/kokuafestival.