This unit provides an introduction to the MIT App Inventor programming platform and the course's first programming project, the I Have a Dream app, which is a soundboard app. Students are introduced to App Inventor’s event-driven programming model. Students first work through a guided tutorial that plays an excerpt of the famous I Have a Dream speech by civil rights activist Martin Luther King Jr. and are then presented with several exercises that challenge them to extend their understanding by solving problems on their own, working in pairs. This is followed later in the unit by several creative enhancement projects where students are invited to express their own ideas by developing their own mobile apps. Students are also introduced to several important CS Principles themes and topics. Two lessons focus on hardware and software concepts. Students get their first look at binary numbers learning how to count in binary and how to view number systems such as binary and decimal, as instances of the higher-order abstraction of a positional number system.