The Census Bureau's Web site [http://www.census.gov] includes American FactFinder [http://factfinder.census.gov], a tool for extracting information from the bureau's vast array of data sets. First, you select a data set, such as Summary File 1 (results of the short form that every household received) from the 2000 census. Then, you select one or more geographic units, such as all the counties in a particular state. Then, you select a table from the data set, such as "Median Age." American FactFinder then displays a Web page with the information you've requested. FactFinder allows you to download the information as a spreadsheet file, so you can sort it and do other analysis in Microsoft Excel.

The Census Bureau also compiles information about other countries for its International Data Base [http://www.census.gov/ipc/www/idbnew.html]. Like American FactFinder, that Web page has an online access tool [http://www.census.gov/ipc/www/idbacc.html] that lets you view selected information and download it as a spreadsheet.

The Centers for Disease Control [http://www.cdc.gov] and the National Center for Health Statistics [http://www.cdc.gov/nchs] also offer downloadable data. The main tool for extracting health data is called CDC WONDER [http://wonder.cdc.gov/]. WONDER stands for "Wide-ranging OnLine Data for Epidemiologic Research."

CDC WONDER includes statistics about deaths, births, cancer, HIV and AIDS, diabetes and other health matters, from the national to the local level. You can select the data you want and then download it as a spreadsheet.