The National Building Museum’s Festival of the Building Arts this Saturday provides a glimpse into the world of construction and design. Architects, engineers, carpenters, furniture-makers, gilders, roofers, and others will be on hand to chat and answer questions. Visitors can lay bricks, finish drywall, and take part in a nail-driving contest. Kids will love the “petting zoo” of dump trucks, cranes, and excavators. Throughout the day, propane-powered backhoes, professional dancers, and ballet students will perform Pas De Dirt, a dance designed specifically for the festival.