Great search engines:

Kids.gov - Find links to government resources for kids and other kids' sites.

PBS.org - Use the search box on the index page to search current events and important events in history.

Sweet Search - Every website on Sweet Search has been evaluated by research experts.

Homework help and online websites for better grades:
Discovery Student Resources - online homework help, games, and step-by-step web math.
Free Math Help - Free math help for students K-12 and beyond, with lessons, games and more.
Hippocampus Free Homework Help - Free education resources for middle school, high school, and college.
Typing Club 

Other great websites:
Mix It Up/Tolerance.org - Learn ways to respond to bullying, prejudice and hate at your school.
Strategy Games for Kids - Games to teach strategic thinking and have FUN!

Career exploration and online quizzes:
Your Free Career Test Online - This free online student-friendly career test takes about 3 minutes and gives you a good idea of some possible careers based on your personal interests.

Research and project links:
Citation Machine: Use this online form to create correct citations for your research papers! Link goes to MLA format.

Easy Essay: FREE registration for a great online tool that will help organize your thoughts and help you create an essay.

Flow Charts/Mind Maps at GitMind:  Tons of really cool flow charts, graphic organizers and designs  you can customize to express and organize your ideas.  Log in for free with your district email by clicking Login with Google.  Click on any design to customize and change to your liking.

Google Scholar

Plagiarism Checker: Plagiarism is a big deal and a big problem. Go to this website to enter your text for FREE and find out if some or all of it can be found elsewhere on the web.

Tom March Thesis Builder: Use this online form to quickly create an outline for drafting a research paper. It will help you see clearly whether you have a strong position for your paper yet or not.