Mentimeter is a free and easy to use educational tool to interact with and engage your students in the classroom. Mentimeter allows students to immediately answer questions from a custom poll, designed by you, using their mobile phones or tablets. Mentimeter is helpful in the classroom as a formative assessment tool. 
 

Prezi is an interesting alternative to powerpoint. It has robust features, is web-based so it can be viewed from anywhere, and teachers can sign up for a free membership with more features than 'normal' free memberships. 
 

QR Code Generator makes sharing information online very fast and easy. These codes are used to take a piece of information from a transitory media and put it on your cell phone. Note: Mobile devices will need a QR reader for your students to scan it.  
 

Wordle is a free toy for generating "word clouds" from text that you provide. The clouds give greater prominence to words that appear more frequently in the source text. You can tweak your clouds with different fonts, layouts, and color schemes. 
 

Padlet is a free application to create an online bulletin board that you can use to display information for any topic. Easily create an account and build a new notice-board. You can add images, links, videos, and more.

Poll Everywhere is an online service that allows you to poll an audience through text-messaging. It's the easiest way to gather live responses in any venue: conferences, presentations, classrooms, radio, tv, print — anywhere.
 

Kaywa QR Code Generator makes sharing information online very fast and easy. These codes are used to take a piece of information from a transitory media and put it on your cell phone. Note: Cell phones will need a QR reader for your students to scan it.
 

Popplet is a free and easy to use platform for your ideas. Popplet helps students think and learn visually. Students can capture facts, thoughts, and images and learn to create relationships between them in realtime.
 

ZooBurst is a digital storytelling tool that lets anyone easily create their own augmented reality 3D pop-up books. Our iPad app is designed compliment our web based storytelling community and help you view your stories “on the go.”
 

Delicious is a free and easy to use tool for saving, organizing, sharing, and discovering bookmarks. Delicious is the worlds leading social bookmarking service and is available on the Iphone, IPad, Android, and Firefox.
 

Khan Academy is a free online service that allows students to learn at their own pace. Students can make use of Khan Academy's extensive library that includes interactive challenges, assessments, and videos from any computer with access to the web.
 

Edmodo is a free social networking service that provides a safe and easy way for your students to safely connect and collaborate, share content, access their homework, and complete polls in a secure online environment.
 

Zip Grade is a free and easy to use application that lets you grade multiple-choice tests using your iPhone's camera as a scanner. It is the most cost effective, fastest, and most accurate way to grade formative assessments in the classroom or where ever you are.

Today's Meet is a free and simple to use tool that allows anyone with the link to today's discussion to connect with your audience in realtime. Today's Meet is an alternative to Twitter that allows participants to use a live web based stream to ask questions and make comments using short (140 character) messages.