Scratch is a new programming language for children from the creator of Lego, Mitchel Resnick. It seems to be built on the same logic a lego, where there are basic building blocks and then you use those to build more complex things. Similarly, Scratch seems to have GUI, which allows you to do things like animate, play music etc using basic building block like symbols.
Here is a BBC article that also contains a cool video of Scratch in action.
Scratch Home Page
Download Scratch
Read: Scratch - A programming language for Kids