Serendipity is a faceted search engine that allows users to explore open educational resources through guided navigation and refinement of searches based on facets. It provides access to over 8000 OpenCourseWare items through dynamic filtering by facets such as creator, language, license, tags, and knowledge area. The document describes various features of Serendipity including faceted exploration, points of interest mapping, open data publishing, and data visualization capabilities to enhance discovery and understanding of open educational resources and contexts.