This is a website for math and its activities that the students can do. You can choose the grade level and the topic and there's different activities that you can do to help them with that topic.
Use this link to search by grade level, subject and theme for classroom activities on a variety of topics. Resource lists with many sites are listed under every topic. There is a little something for everyone here from a wide collection of instructional units.
This website is great! It contains discussions, lesson plans, and resources. This site also includes a state standard search. The curriculum will address grade levels Pre-K through adult learners.
A website full of lesson plans and ideas for later elementary students. Another portion of the site leads to other grade levels for different information. Useful for different experiments and sorted by science subject, ex. chemistry, physics, biology.
I think Weekly Reader is one of the best curriculum suppliment resources. I used it every year I was home schooling my daughter. One of the things I love about it is that it is always current. For example, one of our 2008 issues for children grades 4-6, discussed our process of voting for president and gave the children the opportunity to vote for president. It's not just for elementary levels either; it goes all the way to 12th grade.