Agile software development is a collective term for collaborative working based on a set values and principles, which has become the de facto approach for the software industry, resulting in it being an essential part of the Software Engineering (SE) curricula for many computing degree courses. One of the most popular Agile software development approaches is Scrum which is widely adopted by the software industry and university curricula. Learning Agile Scrum is imperative for students not just as the part of the SE module but for use in the development of their final software project during the course. Teaching the Agile Scrum approach in a way that students can effectively employ in their final project requires the use of some additional practical aid, which is always a challenging task for teaching staff. Employing commercial tools may not be suitable due to additional financial cost, time and learning curve for students. This paper proposes an easy and effective Game-Based Learning (GBL) approach for Agile Scrum using Trello. Trello is a web- based app with no learning curve used to design any project in a collaborative environment. It is not a Scrum tool, nevertheless its features can be transmuted into a Scrum tool to be used to develop projects. Using this Trello-based gaming activity, students can learn the Agile Scrum approach as a game not as a complex methodology. This proposed GBL approach has been used for two undergraduate courses for the last four years, demonstrating constant improvement for both courses in their learning and assessment whilst comparing it with the traditional teaching approach for Agile Scrum.