Most of the maps we use look familiar to us: for instance, most Americans can recognize the shape of the continental United States whether it's appearing on a weather map or in a newspaper article about the economy. Sometimes, however, ordinary maps depicting geographic area aren't the most useful method of visualizing our information.
Erek Dyskant submitted his Census Data Explorer project as part of the Sunlight Labs "Apps for America" challenge. While only a few layers (poverty and race) are available so far, this seems to be a relatively fast browser for visualizing census data at the tract or neighborhood level. It appears to be using OpenLayers and Google Maps, and of course the data comes from the Census Bureau. Good luck, Erek!