Website: Marcia's Science Teaching Ideas

Marcia Krech's website, Marcia's Science Teaching Ideas, is filled with a lot of ideas for teaching Earth science.  There are many files that you can print off and use as long as you keep her copyright in tact.  Many of the activities are paper-based: worksheets, flashcards, etc.  There are some labs and some kinesthetic activities mixed in as well. 

For those of you who don't teach Earth science topics, you might find the sections on the metric system and experimental design helpful. 

Marcia also sells CDs of materials for a variety of topics, if that is something that is of interest to you.  Many of the CDs include PowerPoint presentations related to the topic as well as materials you can print off.  I don't have any first hand knowledge of the materials (just what's listed on her page), as I've only ever perused the free materials. 

Another source to add to your growing list...