Celebrate Earth Science Week, an annual event held during October:
http://www.earthsciweek.org/

Celebrate Geography Awareness Week, an annual event held during November:
http://www.nationalgeographic.com/geographyaction/habitats/gaw.html

Celebrate Geographic Information Systems (GIS) Day, a one-day event held during November. The USGS is a co-sponsor of this event:
http://www.gisday.com/

Digital Library for Earth System Education (DLESE) is a collection of web-accessible teaching or learning materials that include lesson plans, scientific data, interactive computer models, visualizations, and virtual field trips.

American Geological Institute (AGI)
The American Geological Institute is a "flagship" organization for many national and international geological societies and associations, and has a strong commitment to releasing current information about science education activities. See AGI's Member Societies website for an extended list of societies. Many of these organizations have educational resource websites.

Association of American State Geologists (AASG)
The AASG website is a portal to all state geological surveys.

National Association of Geoscience Teachers (NAGT)
National Association of Geoscience Teachers (NAGT) NAGT is a professional organization dedicated to raising the quality of and emphasis on teaching the geosciences at all levels.

National Science Teachers Association (NSTA)
NSTA is affiliated with many science teaching associations and hosts a national conference each year. Many states also have equivalent associations.

National Council for Geographic Education (NCGE)
Since 1915, the NCGE has been the major professional organization for geography educators at all levels.

National Biological Information Infrastructure (NBII)
NBII's website is home to much biological information (including USGS)