The Freshwater Ecology Laboratory at Connecticut College has developed an interactive, Web-based identification key to freshwater algal genera using the Lucid Professional and Lucid 3 software developed by the Centre for Biological Information Technology at the University of Queensland, Brisbane, Australia. The "Key to Freshwater Algae" was funded by the National Science Foundation (Award #CCLI-0229531) to encourage awareness of microscopic diversity through a creative, investigative approach to learning. Users may answer questions in any order to quickly and efficiently narrow down the list of taxa to only those that match the characteristics they have chosen. All characters and terms are clearly explained for ease of use by those unfamiliar with the algae. This non-hierarchical, user-friendly key is linked to Web pages containing a wealth of resources, including images, movies, and information about the morphology, ecology, and reproduction of each organism. These materials are especially well suited for classroom use in conjunction with cultures purchased from the Carolina Biological Supply Company, a popular distributor of biological materials. Cultures from the Carolina Biological Supply Company representing nearly 75 freshwater genera from a variety of algal groups were observed and photographed using high resolution digital imaging to fully document cellular structure and highlight distinguishing features. High quality video footage of each taxon incorporating titles, diagrams, and structural terminology was outputted as QuickTime movies, on DVD, and on VHS cassettes. The "Key to Freshwater Algae" and supplemental materials are available online at http://silicasecchidisk.conncoll.edu to provide an innovative alternative to traditional dichotomous keys that is particularly appropriate for introducing students in undergraduate life science courses to the algal groups and genera.