• US Census American Community Survey: CensusReporter.org
• USASpending.org: http://www.usaspending.gov/data?tab=API
• Bureau of Economic Analysis: http://www.bea.gov/API/signup/index.cfm
• Census: http://www.census.gov/developers/
• BJS: http://www.bjs.gov/developer/ncvs/index.cfm
• Dept. of Labor (especially BLS): http://developer.dol.gov/
• EPA: http://developer.epa.gov/
• PANDA: http://pandas.pydata.org/pandas-docs/stable/api.html

We should pick one of these to work on next, keeping in mind we want to build an extensible API wrapper that plugs in to Geomancer. This is a similar approach to what Open Civic Data does: http://opencivicdata.readthedocs.org/en/latest/scrape/index.html