The Contextual Activity Sampling System (CASS) research methodology and the CASS-Query application have been developed for contextually tracking of activities with a mobile phone. The method relies on frequent sampling of participants' practices and affects during periods of intensive follow-up. Two research designs provide an account of the methodological development work and the possibilities offered by CASS. The first study followed five student-groups longitudinally to examine evolution of academic knowledge practices. The findings from the second year data-collection show that trialogical practices were considered challenging, but often generated optimal-flow experiences. The second study investigated interprofessional work during a clinical course. Based on this pilot study, it was concluded that the data collected about activities and experiences over time extend the understanding of students' practices beyond what can be acquired by post-course questionnaires and can help in development of the design of interprofessional education in medicine and healthcare.