This research addresses the notion that the compatibility of skills and task demands involved in an activity elicits flow-experiences that render the activity intrinsically rewarding. We applied two experimental settings designed to test the causal impact of a skills–demands compatibility on the emergence of flow and intrinsic motivation: a playful computer game (Experiment 1) and a knowledge task (Experiment 2). Results support the balance hypothesis and indicate that compatibility of skills and task demands results in a flow-experience irrespective of the type of activity. This demonstrates the generalizability of flow-experiences across two qualitatively different types of activities. Going beyond prior research the results of Experiment 2 reveal that flow-experiences foster the willingness to reengage in the activity in a free choice setting which represents a behavioral measure of intrinsic motivation.