Due to their characteristics, millennials prefer learning-by-doing and social learning, such as project-based learning. However, software development projects require not only technical skills but also creativity; Design Thinking can serve such purpose. We conducted a workshop following the Design Thinking approach of the d.school, to help students generating ideas for a mobile app development project course. On top of the details for implementing the workshop, we report our observations, lessons learned, and provide suggestions for further implementation.