This article describes a variety of opportunities for educational activities that can be found in the complex, yet easy-to-manipulate, trophic relationships between goldenrod plants, insects that induce gall formation, and the natural enemies of these gallmakers. Gall collection, measurement, and observation (exit holes, larval response, temperature, etc.) can help students develop scientific process skills including observation, classification, measurement, inference, prediction, control of experimental variables, and material manipulation. Galls can also be studied to learn about insect ovipositing behavior and plant responses to three types of gallmakers--each with its own distinct gall type. Likewise, classroom activities can focus on the collection and study of galls to discover principles of ecology and insect life cycles. (Contains 2 figures.)