This is a great math website for elementary and middle school students. It contains a lot of information along with fun activities, games, worksheets, and quizzes.
This is a sample template for a science fair PowerPoint presentation. I found the format to be really easy to understand. Also, because this is a googledoc, every student can access and post their projects online!
Fit kids clubhouse has loads of ideas to engage young students in the learning process. The Preschool Science matters blog introduces a great lesson on solids, liquids, and gas using balloons that I could easily adapt to a 2nd grade level. I love that through this lesson a three year old child made the statement, "a solid is heavier than a liquid", brilliant.
Great video on the "Fifty Nifty United States" it will get stuck in your head but in doing so you will never forget all the names of our country's states. Yay!