This is a wonderful new extension of Geogebra. Students, teachers, professors, and mathematicians are creating interactive "modules" using Geogebra to demonstrate mathematical principles and posting them for anyone to play with and learn from.
Try searching "Pythagoras" and see how many different ways to prove that the square of the hypotenuse of a right triangle is equal to the sum of the squares of the two other legs. (Pythagorean Theorem)
Once you chose the application you want to try, another window will open up and you'll click the link to open the worksheet to access the working parts.
How many of this years math students will create something that we can submit to the benefit of someone else?