Yosemite National Park will be hosting an Earth Day Festival on Saturday, April 21, 2018 from 10:00 am to 2:00 pm in front of the Valley Visitor Center. All activities are free for all ages and entrance to the park is free on Saturday. https://www.nps.gov/yose/learn/news/yosemite-national-park-to-celebrate-earth-day-on-saturday-april-21-2018.htm