One of the interesting things observed on the surface of Ceres is a large white spot, seen below.
As Dawn has gotten closer to Ceres the image resolution has improved and we're starting to see several white spots on the surface.
What are these white spots? At the moment no one knows for sure. They are likely ice depressions/craters of some kind, but we'll know more as Dawn gets closer to Ceres. In the meantime, enjoy the images as they come in and be sure to show your kids. For more information, check out NASA's page on Dawn.