ToonDoo - Create your own comic strip. Just a tip - to create a comic book download your pages as a graphic file and put in a Publisher booklet.
Prezi - Online presentation tool.
National Geographic's new education website.
Study Blue - students or teachers can create free digital flash cards with android or iphone apps. Must create free account. Also check cobocards.com, braneos.com and quizlet.com for flash cards.
Michigan Virtual School - Math, science and technology courses for middle and high school students.
KahnAcademy.org - Over 3,300 videos on everything from arithmetic to physics, finance, and history and hundreds of skills to practice.
WOLFRAM|ALPHA is a computational knowledge engine, not a search engine. It uses built-in knowledge curated by human experts to compute a specific answer and analysis for every query.
Free Online Classes - Take classes from big names like Yale, MIT, and Tufts without ever submitting an application or paying a cent in tuition.