The City of Chicago maintains an informative GIS portal with links to base maps, datasets, and specific interactive maps for various applications, such as airport area sound insulation levels, interactive zoning maps, and West Nile virus infection tracking.
A project of Columbia University, "SEDACs mission is to develop and operate applications that support the integration of socioeconomic and earth science data and to serve as an information gateway between the earth sciences and social sciences." In addition to a host of interactive mapplications, they host a large number of academic data sets on a wide variety of topics.
"The North American Religion Atlas (NARA) provides access to resources for the study and teaching of North American religious history within a geographical and multimedia framework. Using mapping technology, users can view data on religion at national, state or county levels. Text, image, and multimedia formats are also available and contribute to greater understanding of the story of North American religion."
"The Electronic Cultural Atlas Initiative is a global consortium of people who share the vision of creating a distributed virtual library of cultural information with a time and place interface. ECAI is a global consortium incorporating scholars in the humanities, social sciences and history; archivists, librarians and curator; members of non-governmental organization; and information technology researchers."
They've got some interesting uses of maps as atlases containing digital storytelling, as well as links to hundreds of maps and geo pieces related to various aspects of culture.
The Connecticut Community Resource Inventory Online (CRI) allows Connecticut residents to download a variety of maps for every township in the state, including maps displaying topographical, soil and water, transportation, political, and agricultural information.
MapTogether's website development team built this simple interactive database-with-map of local community art fairs in Illinois. Visitors can search for a specific fair or browse through a map of the state and zoom into their particular region. A dynamically-generated calendar of upcoming fairs and associated registration deadlines is available as well.