An oldie, but a goodie! Scratch is a free tool designed to support the development of coding skills. Available in 40+ languages and aimed at students aged 8 and up. Students can program their own interactive stories, games, and animations - and share their creations with others in the online community.
My 5 year old daughter loves Scratch Jr. She had a tutorial from us initially, but was able to use the software independently very quickly, to her own delight.
I have used the computer version of Scratch with students in grades 3-6 (in Australia). My colleagues were amazed when students produced maze games where if the player bumped into the maze walls they were returned to the start - little did they know how easy it was once we got the hang of the coding. Great stuff.
Actually there is also a new curriculum for Scratch with worksheets:
http://scratched.gse.harvard.edu/guide/download.html
It has also been translated into several languages.
This is a very helpful tool if you want to start introducing programming to a class. I have been using it now twice, and I am happy with the outcome. In particular the worksheets are so helpful and give you more time to support the individual child.
I have use code.org as an introduction before using scratch. It allows the children participate it in games involving angry birds, plants vs zombies, flappy birds and the disney frozen characters.
Biteable is a web-based tool that allows you to create beautiful explainer videosto explain key concepts, create instructional guides and tutorials to share with students and many more. You don't need advanced video editing skills to use Biteable. The process is simple and easy. You simply select an animation style from Biteable's template gallery, edit the text and colours, then add photos and music. When your are done editing your video, click on 'Email Me My Video' and your video will be created in a matter of minutes.
Learn the basics of the JavaScript programming language. Create an interactive animation of your own name. A did this activity with a few Year 4 students (8/9 years old).
Codecademy has lots of interactive learn to code examples, older students or students needing extension activities could use the Python tutorial.
Love using this tool in the classroom to explore a range of topics from science to literacy. The coding games and tutorials teach a lot of problem solving, language development and collaboration skills.