Adaptive course generation becomes more appropriate for realistic usage scenarios and more flexible if it includes mechanisms deciding just-in-time which content, which exercises, which external resources, and which tools to include for an individual student. We developed such a just-in-time delivery framework (called Dynamic Items) that is used for enhancing the adaptivity of (educational) online material generated by the web-based platform ActiveMath. This paper describes the framework and discusses several new learning opportunities created by Dynamic Items for an individual student.