Screenr's web-based screen recorder makes it easy to create and share a screencast.  Just click the record button, capture your screen and voice, and share the link.

http://www.screenr.com/

Grammarly is an automated proofreader and your personal grammar coach. Correct up to 10 times more mistakes than popular word processors.

http://www.grammarly.com/

iCivics has produced 16 educational video games as well as vibrant teaching materials that have been used in classrooms in all 50 states. Today we offer the nation’s most comprehensive, standards-aligned civics curriculum that is available freely on the Web.

http://www.icivics.org/

Edheads is an online educational resource that provides free science and math games and activities that promote critical thinking. Choose from Simple Machines, Virtual Knee Surgery or Stem Cell Heart Repair, among others. All activities meet state and national standards.

http://www.edheads.org/

DropItToMe is a free service that works with Drop Box to allow people to upload files to your Drop Box account without giving them access to the contents of your Drop Box. 

After connecting the two services DropItToMe provides a that you can give to your students.  This will enable them to upload files into your DropBox account.  You chooase a password for this file and only give it to the students you want to be able to upload files.

I use DropItToMe so that my students don't clutter my email box with the papers they are turning in.

http://www.dropitto.me

Quiz Revolution

Quiz Revolution is an easy way to make a multimedia quiz for your website or blog.  You can include video, audio, and image file in your quiz. Each question in your quiz can have a different media format. There are two options for answer format, multiple choice or open-ended response. Quizzes are easy to create and easy to embed into a website or blog. If your students register for a Quiz Revolution account before they take your quiz, you can monitor their quiz results. 

http://www.quizrevolution.com/

Chemical Educational Digital Library

The Chemical Educational Digital Library is a large collection of resources for teaching
and learning chemistry.  It contains tutorials for students, 3D models, lesson plans, and more.  It also features a periodic table that links each element to data and explanations about that element.

http://www.chemeddl.org/