Celebrate Earth Day early in Boulder. Join CU Museum of Natural History scientists at Life on Earth Day to explore our special planet and the amazing plants, animals and ecosystems that are warming up and waking up this spring. The FREE, family-oriented science event is Saturday, April 15 from 10 a.m. to 4 p.m. Be prepared to get dirty, as you plant seeds, make art with recycled materials, play music, dissect plants under microscopes, look for critters outside and more. No reservations required. 1030 Broadway, Boulder, 303-492-1666.