The FBI's new data portal; replaces Uniform Crime Reports (UCR). Includes law enforcement data. "Use the CDE to discover available data through visualizations, download data in .csv format, and other large data files."
HUD (US Dept of Housing & Urban Development) provides datasets with information on community/neighborhood conditions, demographics, economic conditions, quality of life, and more. Format varies depending on data and source.
NACJD archives data are largely from federal government sources and are freely available to the public, but some datasets are from ICPSR and require a login. Files are zipped; with a variety of formats available, including SAS, SPSS, Stata.