Another interesting and valuable set of open resources for education is open data.
Google has an excellent collection of public datasets, including extensive tools to visualize and analyze the data.
CERN has recently made available extensive particle physics data along with software for its analysis.
US census data is available including some wonderful visualizations, one of which details college majors and eventual careers.
Data such as this can be used as an investigative tool by students, and in the case of the census data even to inform policy for the educator.
It is important to select data from high quality sources. It is easy to find data that is reflects bias on the part of the researcher or collection agency.