Harcourt School Publishers have many very interesting resources available on their Learning Site. These resources are made to supplement the programs and books by Harcourt School Publishers, but even if you are not using any of their program or books, these resources would still be beneficial. So when starting on a new science or social studies unit, be sure to check out The Learning Site where you will find something to help you. Some of my personal favorites are below:
Science Up Close has got many short videos, interactives and explanations on scientific concepts. You will find resources on topics such as seasons, camouflage, resources, water cycle etc for grades from 1to 6.
In Harcourt Brace Spelling kids can learn spellings in a fun interactive way. Again you will fine resources for grades 1 through 6.
Find simple mapping games and lots of other stuff in the activities area.
Find lots of links for fun interactive social studies here.
Make your own timeline, multimedia biographies etc in here.
Take some time and explore around The Learning Site to find much more in many more subjects.