The purpose of this page is to document sources of data that you can import into the database platform of your choice in order to either do productive work or simply learn.
If you know of any more please email micah "AT" yoderdev "DOT" com, and include "Free Data Source" in the subject. Thanks!
Street level data for the entire world is available!
Data for polling for the current (2014) Senate elections in the US. Small but could be useful.
AWS has a large list of publicly available datasets.