My first recommendation would be http://scratch.mit.edu/ http://scratch.mit.edu/ There are a number of commercial projects, including http://www.stencyl.com/ h

My first recommendation would be http://scratch.mit.edu/ http://scratch.mit.edu/ There are a number of commercial projects, including http://www.stencyl.com/ http://www.stencyl.com/ , http://www.scirra.com/ http://www.scirra.com/ , and http://www.yoyogames.com/ http://www.yoyogames.com/ that are a bit more sophisticated, but Scratch is great for kids.