Cyclopath is a routing and mapping system for bicyclists in the Twin Cities metro area. The system, developed at the University of Minnesota, generates bicycling routes that can be personalized to meet individual cyclists' preferences. Cyclopath is also the world's first full-featured geographic wiki—all users can edit the system's maps of roads and trails. Much information about bike trails and cycling conditions is currently known only to individual cyclists, and Cyclopath allows them to share this key knowledge with each other. Cyclopath is a popular resource for the cycling community and a powerful research platform. In this seminar, Loren Terveen will describe the innovative aspects of the Cyclopath system design, summarize several research studies of Cyclopath users and usage, and describe a few new development and research directions.