In this paper, we take a designer's look at how the activities and data of learning and assessment can be structured in immersive virtual game environments called Massively Multi-Player Online Games (MMOG). In doing so, we examine the channels of evidence through which learning and assessment activities are derived in MMOGs, offering examples of how multiple evidence channels in operation through game-based activities can be utilised to construct rich data trails for assessment. (Contains 4 figures and 3 tables.)