The presenters are developing activity-based course materials for college geometry. Topics are introduced by exploratory activities using Geometer's Sketchpad. These activities are designed to be worked on in small groups. After students have this foundation, readings and class discussions clarify and extend the concepts, as well as providing context and appropriate notation. Then students are expected to demonstrate their understanding through follow-up exercises. Prof. Reynolds is using these materials in Fall 2002. We will report on her experiences and on our further plans as Prof. Fenton uses the materials in Spring 2003.