EXPOSITION PARK. If you’re looking for children’s activities in Los Angeles, the California Science Center is a great source for both fun and education. Billed as the West Coast’s largest hands-on science center, this facility presents informative permanent exhibits on such topics as the Earth’s ecosystems, air and space, and human inventions. Traveling exhibits offer new adventures, and there is even a seven-story IMAX screen that shows 3D movies like “Hubble” and “A Rainforest Adventure.”