Student investment in learning is often stronger when learning incorporates student choice, "real-world" authenticity, and creativity. This action research study investigated the impact of a particular tool for emphasizing these elements in learning: a free-choice, or "Genius Time," project in which middle school students in an independent all-boys school were asked to develop and carry out an individual project to investigate anything of their choosing as part of their regular science class. This study aimed to determine how a project like this could impact student skill-building, self-efficacy, motivation, and student learning through the practice of inquiry. Through surveys, student self-assessment, student interviews, and teacher journaling, the results showed that this project was successful in building essential 21st-century skills, such as initiative, risk-taking, persistence, and resilience. In addition, students were engaged in meaningful inquiry learning because they were required to exercise and grow their own agency for learning, including their self-efficacy. Finally, this project may have facilitated a shift in participant personal motivation toward more intrinsic (rather than extrinsic) factors. These findings support a larger body of research and reporting about the effectiveness of project-based learning, and free-choice or passion projects in particular, to engage students with inquiry in meaningful ways.