
My 12 year old loves this. One, it's free, two it has a large community of supporters. Three it reflects many useful aspects such as modularity, extensibility, object oriented principles, shared code, and graphic development environments. I'm not saying it's the most robust language, nor full of best practices - but you cannot beat it's WOW factor for young teens.
In a few short months my son has made tremendous progress. At first he just wanted to generate a gun and explosions. Then he became concerned with the graphics and spent days combing websites for just the right ogre icon to tweak. Then he discovered arrays and decided he wanted to generate all the monsters from an array. Next he decided his code would be much easier to manage if made all the functionality reside in scripts that he attached to the objects. Now he says he's focusing on revising his physics engine! It's a beautiful thing.
It is contrary to reasoning to say that there is a vacuum or space in which there is absolutely nothing. -- Descartes