Alan Kay is an inspiration for much of my recent thinking about educational technology. If you have any interest in educational technology or the history of modern computers and don't know who he is, go learn about Alan Kay
I'm going to be summarizing a few of his ideas for educational technology here. Briefly, here are some highlights to set up future topics. Alan Kay has been working on educational technology since 1968 when he first visited Seymour Papert. If you're interested in educational technology and don't already know him, go learn about Seymour Papert. And if you don't already know about it, also go learn about Logo.
Alan Kay generally uses Squeak (a Smalltalk implementation) and in particular Etoys when he gives a demo. The combination of these tools have undergone continual refinement since the origins of Smalltalk at Xerox PARC in the 1970s. Some of the original developers of Smalltalk are still actively maintaining them. They're freely available to anyone and run on almost any computer you might care about: Windows, Mac OS, Linux, and even, notably, the XO laptop of the One Laptop Per Child project.