[youtube http://www.youtube.com/watch?v=IqjIC7OXGZA&w=560&h=315&wmode=window&h=315]

Google Blockly is a Web-based graphical programming language that intentionally resembles a jigsaw. You create programs by joining pieces together, and are restricted in the same way puzzle pieces are, by what fits where. It short cuts the process of having to learn correct syntax -- If the pieces fit, the program works. It's an ingenious and easy-to- understand method of ensuring that the program is correct. Take a look.