Increasing concern regarding student disengagement and education's role in helping students to navigate the ever-changing realities of a globalized society has focused attention on the importance of 21st century skills. This mixed-methods study investigated whether and how intensely students experienced optimal engagement during a Spanish project that required them to conduct and reflect on a 30-minute interview with a native speaker of Spanish. Engagement was measured through the lens of Csikszentmihalyi's (1996) flow theory. Findings revealed that authentic, real-world tasks that require students to make use of 21st century skills and which engage learners affectively facilitate behavioral, cognitive, and emotional engagement.