If you have any interest at all in Computer Science you owe it to yourself to try out a few of the interactive courses. John Resig wrote a nice introduction to the program in which he explains how Bret Victor’s amazing talk about responsive programming environments inspired the program:

Rather than starting Computer Science education off by explicitly teaching how a computer works or fundamental programming concepts (like variables, logic, control structures, etc.) you put the student into code of graduated complexity and encourage them to manipulate, explore, and write their own programs.

The key to these courses is the instant visual feedback. Students can use the simple tools to instantly see whether their manipulations are producing the desired results.