Children find secret hiding places everywhere. Give them a blanket and chairs, and—presto!—they’ve created a special spot that is all their own. It’s all the more fun when they can build something together, like at the all-ages Build a Fort event. Kids can use giant boxes and colorful fabric to create imaginative hangouts. The free event will be held on September 12 at 3 p.m. at the Windsor Regional Library and on September 19 at 3 p.m. at the Northwest Regional Library in Santa Rosa. Other local libraries will host fort building in October and November. See sonomacounty.libcal.com.