This article presents an approach to using open-source tools and open-source projects to add realistic and practical examples to a course on software design in a professional master's program of software engineering. Students are encouraged to use object-oriented, open-source software projects available on the Internet, and to analyze their design attributes using open-source tools, to hopefully improve their designs using documented design patterns and other design strategies. The proposed approach provides a variety of realistic examples for study, which can vary from semester to semester, without the instructor having to prepare complicated realistic examples or to rely on over-simplified examples in textbooks. Because the course and the approach are relatively new, a quantifiable assessment of the pedagogical approach has not been presented. However, the argument is made that realistic examples provide for better learning, and evidence is provided to show the feasibility of the approach. The instructor's role is more of a mentor than a traditional teacher, as every open-source project is different from a design perspective.